Nice Job Breaking It Hero / Marvel Cinematic Universe

Bruce: Tony, maybe this might not be the time...
Tony: Really? That's it? You just roll over and show your belly, every time somebody snarls?
Bruce: Only when I've created a murder-bot.

— Tony Stark and Bruce Banner on creating Ultron, Avengers: Age of Ultron

As brought up in Captain America: Civil War, superheroes, individually or as in a group, tend to directly or indirectly cause an amount of the conflict they themselves have to fix later on. This can be attributed to toying with things they don't understand to not sticking around to personally supervise or help with the clean up.

Spoiler Warning: lots of unmarked spoilers below, with some of them being It Was His Sled by this point.

Major Characters.

These characters end up breaking a lot of things, due to 1) the scale of the thing (such as Odin Banishing Thor) and/or 2) Frequently causing little things over time, that build up to something big.

Due to the interconnections of the franchise, many things in one work can spill into others.

The Avengers As A Whole

• The "time heist" the Avengers did in Avengers: Endgame very nearly gave Thanos everything he wanted. The Avengers travel back in time to recover the infinity stones from earlier in their timelines, in order to undo the snap. It all goes off without a hitch, until a past Thanos from 2014 (the year the events of Guardians of the Galaxy took place) discovers the time-traveling Avengers, and captures the present incarnation of Nebula, allowing him to travel back to the present, where the Avengers have already assembled an Infinity Gauntlet for him from Iron Man's armor, essentially stopping just short of gift-wrapping it. Even worse, when this Thanos learns to what lengths the Avengers have gone to in order to undo the snap, he realizes that leaving half of the universe alive was a mistake because the half that remained would always remember what they lost and resent Thanos for it. As a result, Thanos resolves to use the gauntlet to destroy the ENTIRE universe this time, and create a new one where everyone worships him. That's right, Endgame is the movie where the Avengers not only turn Thanos into an Omnicidal Maniac, but also nearly give him all the tools he needs to put his beliefs into action!^note The present day Thanos, who the Avengers manage to slaughter at the start of Endgame, already was one to some extent in Infinity War, but this past Thanos had never gone through the development of the other one, making him less of a Well-Intentioned Extremist in doing so.
• The members of Avengers-199999 who visit L1130, along with the Avengers-L1130, indirectly give Loki (Variant L1130) a chance to escape from custody, setting into motion the events of Loki (2021) and the eventual death of Kang. This will cause one of his variants to replace him, who is a lot more villainous.
• Eternals reveals that Thanos's Snap reduced the energy needed to kickstart the birth of Tiamut, which would destroy the Earth, and thus delayed Tiamut's birth for a few years. So when the Avengers went time-traveling and the Hulk resurrected the Snap's victims, he ended up boosting the population enough to start Tiamut's birth.

T'Chaka

• Everything that happened in Black Panther could be blamed on King T'Chaka. When confronting his brother N'Jobu over stolen Vibranium, T'Chaka killed him to protect Zuri and abandoned N'Jobu's son in the slums of Oakland to preserve the secrecy of Wakanda. Said child would grow up to become the super-terrorist Killmonger who would start a civil war in Wakanda to avenge the death of his father.

Odin Borson

• Odin's banishing of Thor helps show Nick Fury that the Earth is not ready to engage the galaxy, helping him become more paranoid, leading to many of Fury's experiments, including the Phase II experiments to draw enough energy from the Tesseract to create weapons of mass destruction, which drew the attention of Thanos and Loki.
  • Subverted when Captain Marvel revealed that Nick Fury was lying when he said Thor was the reason for his experiments. He was well aware of the existence of powerful extra-terrestrials decades before Thor came to Earth.
• Long ago^note Thor: Ragnarok spoilers, Odin banished his daughter Hela to an unknown dimension; after his death, because he had never told anyone else alive about Hela, she was able to escape and conquer Asgard, forcing Thor to destroy his own kingdom to stop his sister.
• Odin's biggest mistake was how he treated Loki. By favoring Thor over Loki, lying to Loki his entire life, and letting the boys grow up thinking that Frost Giants were irredeemable monsters, Odin positioned Loki to have a psychotic break once he learned the truth — which leads to Loki desperately trying to prove he's a worthy son who's loyal to Asgard while decrying any link to the "monsters," even if that means tricking and murdering his birth father Laufey, sending the Destroyer against Thor, and trying to destroy all the Frost Giants for good. Loki's actions in The Avengers likewise stem back to Odin's bad parenting choices.^note That's not even counting Loki's motivation for disrupting Thor's coronation ceremony to begin with, and goading a hot-headed Thor into attacking Jotunheim, both of which stem back to Loki's loyalty to Asgard and the rivalry in which Odin raised his sons.

Nick Fury

• Nick Fury's experiments -
  • Literally opened the door for Loki and others, saying that the Earth was ready for interstellar war.
    • This also causes power shifts in areas like Hell's Kitchen, leading to the rise of The Kingpin.
  • In Spider-Man: Far From Home: he leaves the Earth and has a pair of well-meaning but under-qualified Skrulls pretend to be him and Maria Hill. Talos and Soren have no idea how to handle the crisis that unfolds, don't know how to contact any superheroes besides Spider-Man, and buy Mysterio's lies wholesale until it's nearly too late, leading to Mysterio's Frame-Up of Spider-Man and revealing his identity as Peter Parker.

Thor Odinson

• Giving Malekith the Aether might have been the only way to stop him (though, let it be said, he was warned by his father, grieving and bloodthirsty as he was), but in doing so:
  • Helped put Loki in charge of Asgard (again).
  • Forces Agent Coulson (noticing a pattern?) to do a cleanup crew in London.
• Perhaps his biggest one was not killing Thanos immediately out of vengeance for the deaths of many Asgardians, Loki and Heimdall included, and stopping to gloat, allowing Thanos to cause the Decimation.

Steve Rogers

• Captain America bringing down S.H.I.E.L.D. due to HYDRA infestation, also:
  • Put Agent Coulson's team through much difficulty, making fugitives from the law.
  • All the loyal SHIELD agents who survived the Hydra purge are now pariahs and wanted as terrorists, because governments don't discern between the two.
  • As part of the Cap's plan to bring down HYDRA, Black Widow leaked all of HYDRA's files onto the internet. Helmut Zemo was able to find valuable secrets among the documents, which enabled him to enact his Roaring Rampage of Revenge against the Avengers.
• Steve Rogers' going against the Accords divided the Avengers worse than ever before, effectively making most of the team fugitives as well.
  • By withholding the truth about Howard and Maria Stark's murders for over two years, Steve destroys all trust that Tony ever placed in him and ruins their friendship.

Tony Stark

• Iron Man films:
  • In Iron Man, Iron Man unintentionally causes the destruction of an Air Force F-22 that attempted to intercept him (before they knew he was a good guy). In his defense, he made sure that the pilot's ejection suit worked properly.
  • Tony Stark revealing himself as Iron Man in Iron Man allows Ivan Vanko to come after him directly in Iron Man 2 in revenge for the transgressions of Howard Stark against Anton Vanko, with all the incidental casualties that may have caused.
  • Similarly, in Iron Man 3, calling out the Mandarin on live television (giving the terrorist his home address and daring him to make a move) means his Malibu house gets bombed, almost killing him and Pepper Potts.
• Tony, under the influence of Wanda's vision and with the help of Bruce Banner, used the Mind Stone in order to create Ultron - an AI which should've ensured the survival of Earth. Then Ultron turned against the Avengers.

  • It is made worse by his later reaction. As seen in the page quote, unlike Bruce who is immediately contrite when faced with what they have done, Tony remains convinced he was right. To the point that in Endgame, in which the disasters beginning from Ultron finally ended in, he still declares his intent to "put a suit of armour around the world" was right (although this can be chalked up to him being delirious and under a lot of stress from having to survive in a ship alongside Nebula following the disintegrations of Spider-Man, Doctor Strange, Star-Lord, Drax, and Mantis, plus the injuries Thanos gave him during their fight).

  • Captain America: Civil War added another layer to that one: the destruction of Sokovia caused numerous casualties, among them was the family of Helmut Zemo, whose Roaring Rampage of Revenge caused the events of the movie.
  • Tony has justifiable reasons for supporting the Pro Accords side. Unfortunately his actions end up escalating the conflict. This includes
    • Shutting down the team's initial discussion of the Accords, when they were calmly and reasonably debating the issue - Tony declares "I win" and stops the talk when Steve (having received news of Peggy's death) leaves the room despite Sam still raising questions.
    • His reasons for confining Wanda to the Compound are valid - however, he fails to inform the team, and more importantly Wanda, of this. Predictably, everyone reacts badly on learning that Wanda is effectively imprisoned.
    • During the airport confrontation he interrupts Steve's attempts to explain the situation and orders Spidey to attack, leading to the disastrous fight which ends with Rhodey badly injured and most of the Anti Accords team imprisoned.
    • His hasty recruitment of the 15 year old Peter into the bigger leagues of the superhero world has severe repercussions for the boy that would carry over several movies.
  • Spider-Man: Far From Home: Tony Stark taking the credit for one of his technicians' virtual-reality projects, giving it a demeaning name and then firing the guy means technician Quentin Beck becomes Mysterio, the guy who almost destroys London and outs Spider-Man's identity while also using a Frame-Up to turn him into a Hero with Bad Publicity. In fact, Mysterio's entire crew are ex-Stark Industries employees (one of whom was the man on the receiving end of Obadiah Stane's "box of scraps" rant) who feel slighted.
    • However, Quentin's story should be taken with a grain of salt for three reasons: 1) he works for Stark Industries, meaning that every project he works on is Stark Industries' property and, by extension, Tony's, 2) Tony himself admits that the name he gives to that project is a shitty one that had to be changed and 3) Quentin mentioned that everyone laughed at the name but, in truth, Captain America: Civil War shows that the audience never actually laughed. Quentin admits he was officially fired for being "unstable", which seems fairly accurate, if not an understatement.
    • More to the point would be Tony's creation of EDITH - the unfortunate implications of a Kill Sat network which can eavesdrop on and murder anyone anywhere in the world aside, he wills it to the teenaged Peter with little instructions on how to deal with it. Predictably Peter, after accidentally almost killing himself and his classmates with it, hands it over to the first sympathetic adult hero to approach him... which happens to be Mysterio.

Wanda Maximoff

• Wanda had a history of this, as her Roaring Rampage of Revenge was what led Tony to create Ultron in the first place. While it's not entirely fair to count that since it was before her Heel–Face Turn, the problem is that she really doesn't get any better.
  • Her lack of control over her powers in Civil War causes the last incident that help the Sokovia Accords get sanctioned. After Crossbones detonates a bomb in an area full of civilians (and strapped to himself), she, while trying to save the people near the explosion, accidentally throws the blast into a building full of people. While she saved the lives of Captain America and the other Avengers and law enforcement officers on the ground, she ended up inadvertently killing some Wakandan diplomats, helping cause the international strife that leads to the Accords.
  • In Avengers: Infinity War, her refusal to accept The Needs of the Many before Thanos gets to Earth leads to the Senseless Sacrifice of numerous Wakandan lives and Thanos getting exactly what he wanted.
  • In grief of losing Vision, Wanda decides to mind-wipe an innocent suburb into play-acting the fantasy of Vision being alive and having children so that she won't have to be alone. To be fair, it was an accident but once she realized what was happening she kept it going before realizing how badly they were suffering.
  • After all of this, it's little surprise when she finally goes Jumping Off the Slippery Slope in Doctor Strange in the Multiverse of Madness.

Peter Quill

• In Avengers: Infinity War, Iron Man, Doctor Strange, and Peter come up with a plan to ambush Thanos and get the Infinity Gauntlet away from him, ending the threat he poses. The plan is going off without a hitch when Peter discovers that Thanos murdered Gamora and, instead of helping the others, he instead angrily strikes Thanos. This forces Iron Man to stop trying to remove the gauntlet and causes Thanos to snap out of the trance Mantis put him in. Spider-Man had just succeeded in getting the gauntlet off of Thanos's hand but him waking up when he did meant that he was able to reclaim it. Thanos was then able to get the Time Stone from Doctor Strange, then go to Earth to get the Mind Stone from Vision and, with all six stones, kill half the universe.

Peter Parker

• Spider-Man: Homecoming: This is pretty much all Peter does. The entire movie is Peter trying to be a hero, botching it, then later is forced to neglect his normal responsibilities as Peter in order to clean up the mess he made as Spiderman, further botching it, and repeat, until he is able to finally apprehend Vulture.
• Spider-Man: Far From Home:
  • Peter hands the E.D.I.T.H. glasses to Quentin Beck, considering him a better choice for "the next Tony Stark". Less than a minute after Peter leaves, it turns out that Mysterio was Evil All Along and was only faking his friendship with Peter to get access to E.D.I.T.H. and use it to cause, then "stop" a catastrophe in London so people will consider him a hero. When Mysterio later exposes Spider-Man's secret identity, it also leads to Damage Control confiscating the glasses, and because their acquisition of the drones was not reversed upon erasing all knowledge of Spider-Man's secret identity, it gave Damage Control a weapon for their later confrontations with Ms. Marvel and She-Hulk.
  • To his credit, Peter goes to a trusted adult to confide in once he has more information - unfortunately, said trusted adult is just another one of Mysterio's tricks, Mysterio going out of his way to make it look like Nick Fury shot him as part of the trick, and he gives Beck the information he needs to go after MJ, Ned, and Betty.
  • More humorously, his Building Swing date with MJ is a wreck. From his super-powered perspective, swinging above the NYC skyline is a fun adrenaline rush; for her, it's downright terrifying.
• In Spider-Man: No Way Home, going to Strange to undo Mysterio exposing his identity in his previous film and getting cold feet right in the middle of the spell results in the dimensions imploding, which leads to numerous universes getting in a harmful collision and villains like Doctor Octopus, Green Goblin, Sandman, Lizard, and Electro terrorizing the Marvel Cinematic Universe. And Peter one-ups that by not letting Strange just return them to their home worlds - the ensuing fight ends up with Peter stranding Strange far away, and when the wizard returns, reality itself is breaking.

Sylvie

• The season one finale of Loki (2021) has her killing He Who Remains. It's too bad that by doing that, it allows another variant of He Who Remains to become the new leader of the TVA, and also allows all the Multiversal chaos that follows to occur.

Uatu

• Uatu continuing his narration when Ultron was silently contemplating the price of wiping out all life in his universe made him aware of The Multiverse, leading to Ultron revising his goal to wiping out all life in the multiverse, even invading Uatu's realm and absorbing his powers to do so.

Mr. Fantastic

• In Doctor Strange in the Multiverse of Madness, Mister Fantastic invokes Reed Richards Is Useless in the most literal manner possible by essentially telling Scarlet Witch how to disable Black Bolt while trying to talk the lunatic down, getting himself and the rest of The Illuminati killed off.

Minor Characters

Unlike the above, the people mentioned here have a lot smaller breakings, due to smaller scale, intent or frequency.

• Agents of S.H.I.E.L.D.:
  • In the penultimate episode of season 1, Fitz - knowing that he and Simmons are about to be executed regardless of what they do - uses an EMP pulse to disable The Clairvoyant's life support system, nearly killing him. Unfortunately, this leaves Raina to inject her dying leader with an unstable, untested cocktail of drugs she was halfway through preparing for him... which makes him super-strong and extremely insane.
  • In the season 2 premiere, we learn that Simmons left S.H.I.E.L.D. because she thought Fitz's recovery from the brain damage he sustained would progress better if he didn't become dependent on her. Unfortunately, this backfires hard: Fitz is literally unable to cope with her leaving, having a complete breakdown that ends with him hallucinating a version of Simmons that he relies on for companionship, support and assistance. Oh, and the effects of his brain damage - already more severe than he realizes - are getting worse as well, possibly because of his breakdown, possibly because Simmons was also his medic and there doesn't seem to be anyone else working towards his recovery. This is later subverted when it turns out Simmons was actually infiltrating HYDRA and Coulson did not want to risk revealing this information to anyone else.
  • In the mid-season finale of season 3, Coulson defeats Ward, the HYDRA agent who betrayed Coulson and his team, became a major adversary of Coulson's, killed numerous S.H.I.E.L.D. agents, tortured and seriously injured Bobbi, tried to have May's ex-husband Dr. Garner aka Lash assassinated, and murdered Rosalind Price, the woman Coulson was in love with. Faced with the option of abandoning him to an almost certain death on a barren planet or killing him right then and there, he chooses the latter. This allows Hive, an Inhuman so dangerous, his own kind banished him to another planet, to assimilate Ward's corpse and return to Earth, as well as accomplishing HYDRA's primary objective of bringing Hive back.
• Jessica Jones (2015): Jessica Jones tries very hard to ensure Kilgrave is arrested and tried to allow Hope to get exonerated. In doing so, due to Kilgrave's powers and connections, many people end up dead or their lives shattered, forcing her to have to let him get ahold of her so she can close enough to kill him herself. She does come out better for it, thanks to being exonerated in court by Jeri Hogarth, but had she killed him from the outset, she and Hope would have been in jail, but a lot of innocent lives would not have been taken in the process.