"We never think, 'How can we get more outrageous or outdo ourselves?'," says It's Always Sunny in Philadelphia creator and actor Rob McElhenney. "We try to think about what in American culture is simply taboo; things that are talked about in living rooms and barrooms but not on television. It's very easy to get mean-spirited because of the personalities of the characters, but it's important to us that the show itself never comes across as mean spirited."
Video: Gay marriage, mysterious pregnancy and more — your sneak peek of the new season
And catch up with your favorite episodes when Season 5 comes out on DVD Sept. 14