I'm a huge Simpsons fan and I agree that seasons 1-12ish are peak TV. The show stays good until like season 15 but definitely starts to slip a little after 12. Nearly all the Treehouse of Horror episodes are really fun. I'm also partial to the Sideshow Bob episodes like Cape Feare where the family has to change their identity and relocate because of him & Sideshow Bob Roberts where he runs for mayor. Nearly every episode is a banger though, the show had so much heart back then.