Daredevil: In Daredevil: End of Days, Daredevil goads Bullseye into killing him by uttering the word 'mapone' in his dying breath. Ben Urich spends the rest of the series trying to learn what exactly that word means. It was the name of his daughter.
If talking to Deadpool, never mention Weapon X. Particularly not "the Workshop." You might get away with it if you were one of the other participants, such as Wolverine, but this is not a guarantee.
Don't hurt kids or those with mental issues. Deadpool has a well-known soft spot for kids, and he empathizes with those who suffer from mental issues (due to suffering from them himself). And if you hurt a kid with mental issues (especially one you have authority over), he goes completely serious and will kill you pro bono. And there won't be a joke, not even a peep, from either of the other comedic "voices" in his head.
Exiles: At the beginning of one issue, the team lands in Canada, with no idea why they're there, until the Hulk lands in front of them. Morph, understandably, turns into a chicken and starts running, but the Hulk just stands there, not even responding to them... until Morph steps on a twig, at which point Hulk goes berserk.
Fantastic Four: Whatever you do, don't mention The Trapster's former villainous handle, "Paste-Pot Pete."
A quick way to get on Doctor Doom's bad side would be by implying that Reed Richards is intelligent, let alone more intelligent than Doom is.
The Incredible Hulk: The Hulk is generally a Berserker anyway, but anything or anyone that reminds him of his father is definitely in for a world of hurt.
Funny: The Hulk and The Thing were up against a single powerful alien fighter, so Thing tries to piss Hulk off.
One surefire way to make Hulk even angrier than usual is comparing him to Bruce Banner, and if it's the Gray Hulk (Joe Fixit), comparing him to the classic Savage Hulk or saying he's not as strong as that version.
As well as claiming to be stronger than The Hulk, especially if you've just knocked him down.
People who disrespect his deceased family (Nicky Cavella dug up his family and pissed on their remains on live television; Frank killed 68 criminals and as a finale gut shot Nicky and left him to die in the woods)
People who go after his children, legitimate or otherwise (Barracuda tried to take his illegitimate daughter; Frank hooked Barracuda's groin up to a live car battery, and left it there for over an hour)
Human traffickers in general (The Slavers do as their name implies and Frank takes apart their operation piece by piece, including throwing the brains of the operation out a 30-story building)
Child abusers in general (He witnesses a Chinese special agent slap a young girl he was sent to rescue and proceeds to literally tear the man limb from limb, only stopping because he was scaring the girl)
Corrupt authority figures (In the infamous The Punisher: The End comic, he shoots the last handful of people who could've restored humanity after a nuclear apocalypse because they were the ones responsible for the nuclear apocalypse to begin with)
Under no circumstances should you insinuate that Spider-Woman is a Skrull. The last time the Dark Avengers did that, she lost her composure and started beating down almost everyone who got near her (and apparently that included Ares), at least until Sentry stopped and calmed her down.
A New Avengers issue added one more for Spider-Woman: Subject her to Mind Control or anything like that and she'll gladly put her hand inside your mouth and BLAST it from the inside. In fact, this pissed her off so much that if it wasn't for Spider-Man stopping her, she would've killed her mind controller.
Venom: The titular symbiote hates being called “parasite”. Justified because, since it is the only one of its kind who wants to bond with its host instead of killing it, and it gives cool superpowers to its hosts, the term “parasite” sounds ungrateful.
The Ultimates: Herr Kleiser, a long lived alien that worked for the Nazis back in the day, is having a last fight with Captain America, and he's wining. But then, he asked him to surrender and request a mercy kill. This idea enraged Cap so much that he got an Heroic Second Wind, turned the tables and Kleisser, and asked "Surrender? SURRENDER??!! You think this letter on my head stands for 'France'?!"
Ultimate X Men: Don't talk trash about Sabertooth's fur coat. At least, not unless you've got a Healing Factor to survive the ensuing violent temper tantrum.
Wolverine has a few, but the most enduring and unchanging one is any kind of brain tampering. Due to his history, he's not a fan of it, and in fact, tried to killNick Fury for doing it to him, since he would've done what Nick had asked anyway.
Mentioning or even thinking Just Following Orders in front of Holocaust survivor Magneto is a really, reallyBAD idea. You'd be lucky enough just to have only your metal fillings removed.
Storm used to have a bad case of claustrophobia. Villains trying to take advantage of this these days are far more likely to piss her off than make her freak out.
Young Avengers: Stature is quite protective of her father's legacy. If she perceives someone attacking her father, she will grow as large as she is able and try to crush them. Unfortunately, this ends up costing Stature her life.
Hulk/The Incredible Hulk (2008): It's pretty much a given you won't like Dr. Bruce Banner when he's angry. Tormenting him is bad enough. Just look at Betty Ross the wrong way, however, and.... HULK SMASH!!!
Thor is grudgingly willing to leave Jotunheim without a fight, until one of the Frost Giants calls him "Princess". Then it's on. This is the Wolverine of the Norse Pantheon. He was the embodiment of the rowdiest, strongest, most fearsome Norse warriors: berserkers. It's carried through in the adaptations. Becomes funnier when you see the look on Thor's companions' faces when it happens. Loki puts it best: "Damn".
Pretty much any insult will push Thor to a towering rage, at least before he learns humility in his banishment to Earth.
While we're on the subject of The Avengers, several of the heroes, Dr. Banner aside, seem to have a button-pushing issue at some point.
Cap doesn't like Tony's selfish attitude; when Tony suggests he would Take a Third Option to laying his life down for a comrade, Cap finally has enough and tells him to suit up, intending to fight him.
Clint Barton/Hawkeye does not take kindly to learning he was Loki's unwitting pawn and as such, responsible for several deaths and nearly killing Black Widow.
Don't tell Thor to put his hammer down. As Cap found out, he'll put it down...on your head.
In general for Stark, his complicated relationship with his father. Part of the reason Tony and Steve don't get along is because Steve unintentionally pushes that button. Invoked by Zemo in Captain America: Civil War to drive the two apart.
Don't touch Peter Quill/Star-Lord's Walkman, or you will be in for a world of pain. Initially Played for Laughs, it later turns out that this is because it's one of the only things he has left to remember his mother by.
Rocket Raccoon does not take kindly to being called an animal. This is because he's the result of several horrible experiments, was taken apart and put back together again, then had cybernetic implants put in, seemingly while he was awake and conscious.
In Avengers: Age of Ultron, Ultron completely loses it whenever someone compares him to Tony Stark. Or even hints that he might be connected to Tony Stark. Such as Ulysses Klaue learns.
The Wolverine: Threatening people Logan cares about will make him go berserk, which is pretty normal. Causing unwarranted suffering on wild fauna, however, also puts him on a violent warpath.
Calling Daisy Johnson Skye, the name she chose for herself without knowing her birth name, will result in Cal angrily screaming, "That's not her name!" Later, however, after her birth name is revealed, Coulson refers to her as Daisy in conversation with Cal in an attempt to placate him, only for Cal to scream at him for that and rail about how she's Daisy to him, but not to anyone else. Coulson doesn't know what to do with this.
Wilson Fisk is a walking case of hot buttons that can cause him to fly into a rage at any moment.
Vanessa in general — don't screw with his relationship with her. Anatoly learns it the hard way. So does Leland Owlsley. He even goes postal in Season 2 on Matt when Matt uses the threat of barring her from ever reentering the United States to bluff Fisk into admitting his complicity in Frank Castle's escape.
Also, involving his loved ones in his business, which includes even talking to his mom. As Ben Urich learns the hard way.
Even scarier, Fisk's button seems to be time-delayed; he's perfectly capable of holding a fairly polite conversation for an indefinite time, even while furious, before erupting like a volcano.
James Wesley's death creates several new buttons for Fisk.
Upon finding Wesley's body, Fisk beats Francis up for failing to protect Wesley.
In Season 3, Karen deliberately visits Fisk with the intention of trying to provoke him into attacking her so he'll violate his parole and the FBI will send him back to prison. She tries to do so by bringing up how she was with Ben Urich when he spoke to Fisk's late mother Marlene Vistain, but that doesn't deter Fisk, and he counters by revealing his knowledge of Matt's double life as Daredevil. So Karen tries again by revealing that she killed Wesley, which is enough to get Fisk to snap and prepare to attack her, only to be stopped by Foggy showing up in the nick of time. So Fisk resorts to putting out a hit on Karen, and tasks Dex with carrying out the job.
And when the hit fails due to a combination of Matt's intervention and Ray Nadeem standing up to Dex, Fisk proceeds to beat to death the agent who passes this news onto him.
What drove Matt Murdock to vigilantism was when he overheard a father molesting his daughter, and no one did a thing about it.
Elderly and children being harmed are two buttons for Matt. In fact his opponents love to specifically target such victims to lure him into traps. Early in Season 1, the Russians abduct a child off the streets as bait for Matt. Later in the season, Fisk has Elena Cardenas (an elderly woman Nelson & Murdock are representing in a landlord dispute) assassinated specifically to lure Matt into an ambush by Nobu.
Frank Castle in one scene is buying guns and ammo from a pawn shop, and then proceeds to ignore the owner as he offers him all kinds of illegal items, until he mentions child-pornography. Cue pawn-shop owner being beaten to death with a baseball bat.
Cornell Stokes hates being called "Cottonmouth". Woe behold anyone who uses that name within earshot of him.
Shades: I suggested we wait [before shooting up Pop's barbershop]. Tone: Wait? Wait for what, Shades? You ain't even down with the clique! You can't give orders. It was loud 'cause it's supposed to be! Niggas need to know you don't rob Cottonmouth- Cottonmouth:[gets in Tone's face] MY NAME IS NOT COTTONMOUTH!! [Tone, who up until this moment had been very self-assured, shakes with fear] Tone:[stammering] My—my bad. My bad!
Don't call Mariah Dillard "Black Mariah" to her face either. And most definitely don't accuse her of having wanted to be molested by her uncle. You know she's changed for the worst in Season 2 when she embraces her villainy and doesn't so much as flinch when Luke addresses her that way.
Bushmaster is very insistent on correcting people who refer to Mariah with her married name with a rather forceful "STOKES. Mariah Stokes."
Don't ruin any of Hulk's glass figurines. You will be punished.
In one episode, we learn that Rocket Raccoon does NOT like being called a "mascot".
Hawkeye: I see you're still traveling with the talking pencil and the furry mascot. Rocket: (jumps onto Hawkeye's chest, grabs him by the throat, and shoves a gun into his nose) Call me "mascot" one more time. Please.
In Spider-Man: The Animated Series, Spidey quickly picks up on and exploits Scorpion's dislike of being insulted and called names to break his focus. Scorpion does get slightly better with this by later seasons, though making fun of his mother still proves a surefire method of riling him up.
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