Most sitcoms have become unwatchable by the time they reach season 15. But thanks to a team of writers determined not to repeat themselves and a cast with a deep love and appreciation for their characters, It’s Always Sunny in Philadelphia keeps moving from strength to strength. By all accounts, the show’s fifteenth season should be a forgettable bore and the show should’ve become a shadow of its former self years ago. Against the odds, It’s Always Sunny – which has been renewed up to season 18 and probably won’t stop there – has just pulled off one of its strongest seasons to date.