What The Biggest Fans Don't Know About It's Always Sunny

When "It's Always Sunny in Philadelphia" premiered back in 2005, its creators probably weren't expecting it to be one of the longest-running sitcoms of all time, but the crude and cringe-inducing comedy has proven to be a massive success. However, even if you've been a fan since the very beginning, there are still some facts about the production of the show that may surprise you. From the on-set scare that made one actor leave for the day to the horrible injury that Kaitlin Olson had to work through, let's take a look at some things that even big fans don't know about "It's Always Sunny in Philadelphia."