It's Always Sunny in Philadelphia is TV's longest-running live-action sitcom. Other sitcoms tend to lose steam after the fifth or sixth season, but It's Always Sunny in Philadelphia has remained relevant and popular for over a decade.

Season 15 of the sitcom aired in 2021 on FXX, and a 16th is on the way. There are some hilarious running gags on the show that fans love. It's Always Sunny continues to strike a chord with audiences because the humor is go-for-broke, unafraid to be offensive, bolstered by hilarious performances.

Dee Is A Bird

Dee in It's Always Sunny In Philadelphia

Sweet Dee (Kaitlin Olson) is treated the worse by the gang on It's Always Sunny in Philadelphia. She is called many different names by the gang on the show, but one name has continued more than any of them, calling Sweet Dee a bird.

It is a running gag that has continued throughout the show. It is funny because it is so stupid and immature. It's amusing to watch how angry Sweet Dee becomes after being called a bird.

Charlie's Illiteracy

Charlie Kelly in It's Always Sunny In Philadelphia

One of the traits of It's Always Sunny in Philadelphia is that it is a show that isn't afraid to make fun of things that other shows would be afraid to make fun of. Sure, they are plenty of shows that have the dumb character. Still, not many shows would make fun of illiteracy the way It's Always Sunny in Philadelphia makes fun of Charlie (Charlie Day)'s.

A sensitive topic that would be the basis for a tender episode on a 70s or 80s sitcom, or a serious episode in a drama, is a running gag in It's Always Sunny in Philadelphia.

The Lethal Weapon Sequels

Lethal Weapon It's Always Sunny In Philadelphia

There is a running gag on It's Always Sunny in Philadelphia about the gang making Lethal Weapon movies.

It is a funny gag because the gang not only doesn't have the rights to the film franchise, but they cast themselves as actors, writers, directors, and producers of the movie. And they are lousy filmmakers.

Dennis Is A Criminal And A Serial Killer

Dennis in It's Always Sunny In Philadelphia

There are hints throughout the show that Dennis (Glenn Howerton) may be a criminal and a serial killer.

He has an explosive temper, he can't remember what feelings feel like, he keeps trophy sex tapes, he keeps duct tape and zip ties in his car, he thinks he is God, and there's a creepy implication with Mac (Rob McElhenney) in episode three season six, "The Gang Buys A Boat." All those things and more could mean nothing... or it could mean that perhaps Dennis is secretly a serial killer.

Uncle Jack and Charlie

Charlie and Uncle Jack It's Always Sunny In Philadelphia

A running gag throughout the show is that Uncle Jack (Andrew Friedman) may have abused Charlie. He is very touchy with Charlie when he is around him, and it is obvious that his touching makes Charlie uncomfortable. Uncle Jack has a weird obsession with his hands in general. He even wears fake hands to make his hands look bigger.

The famous Season four episode 13 The Nightman Comethmay be a play about how Charlie was abused by his uncle.

Frank's Shady Business Dealings

Egg It's Always Sunny In Philadelphia

Throughout the show, there is a running gag about Frank (Danny DeVito)'s businesses.

It isn't wholly known all the shady business deals Frank has invested in, but he has had some shady businesses in the past. He's heavily implied to be seriously sketchy.

Charlie Work

Charlie Work It's Always Sunny In Philadelphia

Charlie work is gross things that no one else in the gang wants to do, like killing rats, cleaning urinals, slime, or sludge. There is an entire episode about a typical day of Charlie work, titled Charlie Work season 10, episode four.

The other members of the gang often sit around all day telling jokes and drinking beer. In comparison, Charlie is left to do all the demeaning, disgusting work.

Cricket's Downward Spiral

Cricket

Cricket is first introduced as a clean-cut guy entering the priesthood, until he runs into Sweet Dee. He is in love with her and gives up being a priest. Dee rejects him, and Cricket's life takes a downward spiral after hanging out with the gang, especially Sweet Dee.

The running gag is how worse Cricket's life has become every time the viewers see him again. Cricket isn't the only person whose life becomes worse after encountering the gang. Other people's lives are worse too, but Cricket is the longest-running gag.

Charlie Stalks the Waitress And No One Knows Her Name

Charlie Work It's Always Sunny

A running gag that started early in the series was Charlie's obsession with the waitress (Mary Elizabeth Ellis). Charlie goes to great lengths to show his devotion to the waitress. He is madly in love with her, and no one in the gang knows her name.

An interesting twist to the running gag is that Charlie Day and Mary Elizabeth Ellis are married in real life.

Mac's Homosexuality

Mac's Dance It's Always Sunny In Philadelphia

Mac's homosexuality has been a long-running gag on the show. Although Mac often chased and slept with women, he was really a closeted homosexual. He may have feared coming out because he didn't know what the gang would think of him or because of his religious beliefs.

Mac finally came out in season 12 as a gay man and eventually expressed his homosexuality through dance in season 13-episode 10, Mac's Dance. The running gag then switched from Mac as a closeted gay man to Mac trying to find his place in the world as an openly gay man.

It's Always Sunny In Philadelphia can be watched on FXX or streamed on Hulu or Fubo TV. Show episodes can be rented on Apple TV, YouTube, Google Play, Vudu and Amazon Prime

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