PotD sure hates Lisa. Did Zeus make a bunch of alts to vote spam those episodes?
Anyways, I haven't seen the Gaga episode, so I guess Another Simpsons Clip Show. I'm kind of disappointed the first clip show made it - I understand why, but the April Fool's gags are classics.
How did Barts Girlfriend end up on this list at all? Can't remember too much about the episode but from what I recall it wasn't unusually unfunny, gimmicky, controversial, centered on an unpopular character or any other usual cause for an episode to appear on a list like this.