The entire episode "Deliver Us From Goodness," which is also a pretty light-hearted, humorous episode, a sharp contrast to the tone of the other episodes.
The ending of "Seymourlama". The obnoxious teenage boy finally gets what's coming to him when it is revealed that he isn't the next Dalai Lama. His parents, whom he had been bossing around the entire episode, kick his ass.
The end of "Monsters in My Room" when the bogeyman pokes his head around the closet door, sees Seth Green's character, gives a terrified little scream, and ducks back out of sight.