This list introduces a variety of Simpsons facts which you probably don’t know but have wondered about – basic questions like “Where is Springfield?” and “Why are all the characters yellow?” to more elusive questions like “Where did ‘D’oh!’ come from?” and “Who has been the highest-profile celebrity to appear on the show?” If you’re curious to learn more about one of the world’s favorite dysfunctional families – still running strong after 27 seasons – check out our list of 25 Simpsons Facts You Probably Never Knew About.