“Lisa’s Substitute” – Season 2, Episode 19
Legally, anyone creating a best-of Simpsons ranking has to include “Lisa’s Substitute.” And for a good reason: It’s a perfect episode about Lisa meeting a joyful and supportive substitute teacher who leaves shortly afterward, destroying her in the process. It’s an example of how the show isn’t just great at jokes, but also at telling heartwarming stories. (And let’s ignore the shitty joke in season 25 where he briefly returns but Lisa is too busy to see him. Fuck I hate that joke so much.)
