Over the past 14 years, FX’s It’s Always Sunny in Philadelphia has gone from a lo-fi situation comedy with a cult following to a pop culture sensation with millions of fans across the world. The series is now 13 seasons in, with another one on the way, and one of the most surprising things about the show’s longevity has been its ability to remain fresh and unpredictable after all these years. It has done this by continuing evolve, shaking up its formula, and more importantly, developing its characters.