I'm not saying this is the best episode, I'm saying it's one of my favorites. It's so outside the normal storyline and clearly that the writers decided to have one of the goofiest episodes they could ever possibly write on this occasionally very serious and often beautiful show. I like shows that are willing to do a comedy episode or an episode completely outside the normal story line to show how the world of the episode is effected by things that happen to the characters.
Basically, while this isn't the best episode, it's goofy and fun.