It's Always Sunny In Philadelphia's "The Gang Squashes Their Beefs" sees the crew trying to make peace with their many enemies - which predictably doesn't go so great. For fourteen seasons now, the gang from Paddy's Pub - Dennis, Dee, Frank, Mac, and Charlie - have shown there are few depths they won't sink to. They're all horrible people to varying degrees, with the show somehow mining hilarious gags from just how vile they can be; it also helps that no matter how offensive they get, the joke is always on them.
It's Always Sunny In Philadelphia slowly built up a fan base, with the show gradually becoming bigger and bigger as word of mouth spread. While the first season is entertaining, it was the arrival of Danny DeVito's Frank in season 2 that the series found its comic groove. Fifteen years after it began there are few signs of its stopping, with its most recent series wrapping up in late 2019.
It's Always Sunny In Philadelphia's main characters have done little to improve themselves since the show began, and in some ways seem to have gotten worse. It's Always Sunny In Philadelphia's season 9 finale "The Gang Squashes Their Beefs" finds them in a rare mature moment, as they realize the various enemies they've built up over the years are starting to impact them too much. They decide to invite their assorted foes over for a Thanksgiving feast to squash their many beefs - which Charlie takes to mean they'll literally be serving beef and squash for dinner.
A big problem with their approach is that it's typically hollow and self-serving, as Dennis just wants his enemies to sign a document stating their beef is squashed, but he fails to offer an actual apology in return. It's Always Sunny In Philadelphia "The Gang Squashes Their Beefs" sees the return of fan-favorites like the McPoyle brothers, Bill Ponderosa, Rickety Cricket - who wasn't invited - and others, but few tensions are eased throughout the meal. If anything, the beefs just seem to get worst, with Liam McPoyle (understandably) still upset about his missing eye and the lack of any apology for it.
It's Always Sunny In Philadelphia "The Gang Squashes Their Beefs" ends with a massive food fight, and once the gang discovers a raging fire, they take an unusual tack - they lock everyone else in the apartment and decide to go to Charlie and Frank's place to watch Thundergun Express. It's a dark ending but since they at least embrace the idea they'll always have each other - as tragic as that sounds - it's slightly optimistic too.