As a Fridge subpage, all spoilers are unmarked as per policy. You Have Been Warned.
Fridge Brilliance:
- "The Gang Gets Quarantined" stands out as an extremely rare case of the Gang fully getting along (minus Frank's obsession with germs) as they prepare for a singing contest: Charlie encourages Mac's dance moves, Dennis pushes them to practice their singing routine without being controlling, and the guys even praise Sweet Dee for a "tragic backstory" and accent she made up. Throughout the show, the Gang often only truly unite when singing in harmony; therefore when their latest scheme involves singing, they stay united and harmonious through the whole experience.
- Several moments in “The Nightman Cometh.”
- Charlie originally wants Dennis to play the Nightman before Dennis and Mac switch roles. Who better to play the ambiguously rapey Nightman than the ambiguously rapey Dennis?
- Gladys “shushes” Charlie and Charlie says “Please don’t shush me.” While small, it could be seen as setting up the Gang’s intense dislike of being “shushed” that becomes a plot line in “The Anti-Social Network.”
- During the entire series, Charlie is only seen behind the wheel of a car once, and during that instance (in "The Maureen Ponderosa Wedding Massacre") Mac comments that it's been a long time since Charlie has driven a car. Not much else is made of it, but Charlie lacking a valid driver's license would make perfect sense— it'd be pretty hard for someone who's nigh-illiterate to study for a driving test, and it would also impair his ability to read road signs and street names. He's also terrified of leaving the city (or was, at this point it's somewhat less), so he never needs to travel long distances by himself.
- He does mention borrowing Dee's car in "The Gang Finds a Dead Guy" (though isn't shown driving it), but this could be Early-Installment Weirdness.
- He also mentions in "Paddy's Pub: The Worst Bar in Philadelphia" that he followed Korman home and put him in the trunk of his own car, which is now outside the bar, so he must have driven it back to Paddy's, but this isn't shown either.
- During the episode "Mac and Charlie Write a Movie", Frank loves Dennis' idea of filming an action movie that features full, uncensored scenes of graphic sex. This foreshadows the conflict that he has with the Gang regarding the Lethal Weapon 6 film they made together, in which he wanted to include a scene of himself having sex with a beautiful woman.
- When Dennis gets a job at the Oldies Rock Cafe in "The Gang Sells Out", The Waitress admonishes him for breaking the rules, even though (earlier in the episode) she could be manipulated into ignoring breaches of conduct if Dennis was involved. When she confronts him, it's while he's doing shots with a bunch of college girls. The Waitress was jealous and lashed out because of it, forgetting that she should turn a blind eye so Dennis won't think less of her.
- When Charlie first plays his song "Nightman" in "Sweet Dee is Dating a Retarded Person," everyone points out that the second half of the song sounds like a description of a man breaking into Charlie's room and raping him while he's asleep. A season 1 episode had already implied that Charlie has an uncle who may or may not have molested him, and the implications get worse every time the uncle appears.
- The title is It's Always Sunny in Philadelphia but the opening credits show Philadelphia's sights at night, making the irony of the title apparent in every episode.
- The cast's general flanderization over time is basically intentional in-universe, as the gang's self-indulgent and bizarre shenanigans make them more self-indulgent and bizarre. Frank even sets about trying to make himself more depraved.
- In the season 6 premiere, Dennis says that Mac owns literally nothing in the apartment. Seems impossible, but then you remember that when Mac had faked his death in Season 4, Dennis went through the apartment and threw away everything of Mac's ("Goodbye Mac's shit, goodbye Mac's shit...").
- In season 10, the Waitress says that she still has a flip phone and doesn't use the Internet at all. At first it seems like a joke about how horribly uncool she is, but remember, she's been the victim of a very persistent stalker for over a decade. It makes sense that a woman in her position would want to stay as off-the-grid as possible.
- "Mac Day" states implicitly that every member of the gang gets their own day to decide what is done. That means there is a Charlie Day. Who plays Charlie? Exactly.
- In "High School Reunion," an astute viewer might realize a few seconds early that the dance scene is a fantasy sequence because their choreography incorporates Dee's backbrace - which she was clearly not planning to wear that night.
- "The Gang Turns Black" doesn't include any scenes in Paddy's or Charlie/Frank's apartment. All we get to see is Dee's apartment, Dennis' car from the outside, the street, the police station, a public electronics store, under a bridge and a nursing home where apparently Old Black Man actually belongs. All places that Old Black Man could have seen.
- In "Sweet Dee Gets Audited" there is a debate between the characters about what to do with the corpse of a dog that is rotting in the alley behind the bar. Mac and Charlie want to perform a "dog funeral," while Frank and Dennis want to throw the corpse in the dumpster. Mac probably supported the dog funeral because other episodes have shown that he still owns an old dog that he is emotionally attached to, so it makes sense that he wants to bury the dog with dignity. In addition, Mac is a hardcore Catholic, so it makes sense that he would place so much value on a proper burial. Alternatively, Frank has expressed the opinion that a dead body is essentially trash, to the extent that he does not care what happens to his own corpse when he dies. Dennis has expressed the opinion that eating a dog is no more morally wrong than eating a chicken.
- In the season 2 episode "Dee and Dennis get a New Dad," when Frank and Barbara meet for the first time since their divorce, he makes fun of her age by saying she has a "turkey neck," and in "Dennis and Dee's Mom is Dead," it's revealed that she died from a "botched neck lift." It would seem that Frank's comment actually did get under her skin, making him indirectly responsible for her death.
- In "Who Got Dee Pregnant?" Dee's supposition that one of the gang is the baby's father takes on a bit of Fridge Humour when one realizes that Kaitlin Olson was actually pregnant at the time, and that Rob McElhenney (Mac), her husband, was the father. So technically, Dee wasn't lying...
- In "The Gang Solves the Gas Crisis," Charlie suggests that the gang count how much gas is going into every car in order to measure how much gas they're selling total, and Dennis mocks him for it: "How exactly are you planning on counting a liquid?" However, the Gang are at least nominally bartenders, and bartenders measure the amount of liquor they're free-pouring into a glass by counting, one number for every half-ounce.
- In "Sweet Dee Has A Heart Attack", Mac and Charlie get jobs in the mailroom of a company to get insurance, and Charlie eventually becomes obsessed with employees called "Pepe Silvia" and "Carol in HR" that he can't find, and believes are made up. Mac claims they are real, but the only way Charlie could have gotten those names was by reading the addresses on the letters, and he's frequently (though not in this particular episode) shown to be illiterate. Perhaps he misread "Pennsylvania" (the show takes place in Philadelphia, after all) as "Pepe Silvia", and "Care of HR" as "Carol in HR".
- Every time the Gang needs Cricket, they just know exactly where to find him, even though he lives on the street and is always in a different spot. Charlie eventually accidentally reveals that they implanted a GPS tracker into Cricket without his knowledge. They just need to check their phones to see his location.
Fridge Horror
- So Dee's neighbor Gary was the serial killer. That explains how he knew the shears would cut though bone. The gang insists that Dee doesn't fit the victim profile, but he's clearly attracted to her. Was he just biding his time? Did she really not fit the profile well enough to murder? Did he kill all those other people because Dee was taking advantage of him? It's possible Gary could have been hiring his past victims to water his plants to lure them into his apartment alone. In which case, Dee's neglect of the chore might have actually saved her life. And given that Gary's victim profile was young blonde women, could the Waitress have been next?
- Another implication is that the profile was modelled after Dee herself, and the women being murdered were targeted because of their resemblance to Dee and Gary was using them as stand-ins. In which case, the gang discovering his secret definitely saved her life as it would only be a matter of time before he finally moved on to his actual target.
- In “The D.E.N.N.I.S. System” we learn that after Dennis is through psychologically manipulating women into falling for him only to abruptly dump them, Mac and Frank swoop in to sleep with them. Mac pretends to be the sensitive nerdy wallflower type to disarm them. Frank is just Frank. The women Dennis gaslights, mentally abuses and sexually uses (and that Mac does a sped-up version to) are so broken by this they will sleep with Frank due to shattered self-worth.
- In the season 6 premiere, Dennis tells Mac that he hasn't had feelings since he was 14 years old. Come season 11, we find out that Dennis was statutory raped by a fifty-year old librarian when he was fourteen.
- In “Frank vs Russia”, he projects to lampshaded creepy levels that all men have a childhood relationship with their mother where she makes him feel powerful (like, say, a golden god) but powerless and dependent at the same time, and he’ll crave her approval for the rest of his life. While the implications of that are not great on their own, it’s pretty likely that Ms Klinsky reminded him of Barbara.
- After Country Mac's death in "Mac Day," none of his closer relatives show up to claim the body, and it's up to Mac and The Gang to handle the funeral. It's entirely possible that the reason he came to Philly in the first place is that he was disowned by his family for being gay and had to leave his home. Considering not only Mac's own internalised homophobia but the fact he's later rejected by his father when he comes out, his uncle Donald being "funny" and being disliked by Mac, Luther (Mac's father, Donald's brother) and his own father, and the fact that Mac's gay cousin Brett from the first episode is never seen again after his one appearance and doesn't appear to be close with Mac either, the larger McDonald family appear to have horrible issues with homophobia, which would tie in with this.
- "The Gang Gets Quarantined" and later episodes reveal Dee is an alcoholic. Dee was a surrogate mom for Carmen in Season 6. What are the odds that she remained sober for the entire pregnancy? Especially since her first instinct minutes after delivery is to suggest they go get beer.
- In "The Gang Solves North Korea", Charlie and Dennis both briefly compete for a girl who is revealed to be only 12 years old. Charlie falling for her is largely due to a combination of his own immaturity and the girl being Younger than She Looks, but Dennis' attraction makes disturbing sense when you consider the running joke about him having a tendency to date barely legal women, and only seems to draw the line at 18 because of the law. While he didn't realise her age consciously, his attraction is uncomfortably in-character.
