BackFire
Mine, if pressed, would have to be the episode where Homer is reunited with his mother. It's not the funniest episode, but it's a perfect example of what made The Simpsons such a beautiful show while in its prime, it was profoundly touching, all the while still being hilarious. This episode in particular.
The final scene when Homer says goodbye to her is both heartbreaking and heartwarming, all the while still having a good gag. Then as the credits roll, after his mother drives away, we see Homer sitting on the hood of his car looking up at the stars. One of the most touching moments in the shows history, just such a feeling of humanity in that episode.
Honorable mentions -
When Bart and Lisa join opposing hockey teams and become vengeful and bitter towards eachother, only to realize how much they truley love and cherish eachother. When they have the flashback to their memories of eachother, it's hard not to get a little choked up.
In the episode about Maggie being born, at the end we see Homers office and it says "Do it for her".
The final scene when Homer says goodbye to her is both heartbreaking and heartwarming, all the while still having a good gag. Then as the credits roll, after his mother drives away, we see Homer sitting on the hood of his car looking up at the stars. One of the most touching moments in the shows history, just such a feeling of humanity in that episode.
Honorable mentions -
When Bart and Lisa join opposing hockey teams and become vengeful and bitter towards eachother, only to realize how much they truley love and cherish eachother. When they have the flashback to their memories of eachother, it's hard not to get a little choked up.
In the episode about Maggie being born, at the end we see Homers office and it says "Do it for her".