The basic plot: Bart takes on Nelson Muntz and wins.
I can’t decide what’s better about this episode: the introduction of Nelson Muntz or the introduction of Grampa Simpson. Both will go on to play huge roles in this show, and it’s difficult to imagine the series without either of them. My first instinct is to declare Nelson the bigger influence here, if only because his catch-phase is so meme-tastic, but I suspect Grampa is the more significant addition — he provides backplot, an explanation for why Homer (and by extension Bart) is so screwed up, and he’s just damn funny.
Put another way, Nelson is — until quite late in the show — essentially a one-dimensional character. He’s the show’s bully, the embodiment of everyone’s nightmares about grade school. In that sense he’s someone we can all relate about, if not necessarily to. Grampa, on the other hand, is epic from the beginning: even before we meet him, we know he’s going to be a bit different. (“Remember the fight he put up when we put him in the home?”) Cut immediately to the first of many cranky letters, and see him taking a swipe at the people who were taking swipes at “The Simpsons” for being degenerate humor. Note we still meet these people today, and they’re just as wrong now, though there are a lot fewer of them.
This is actually pretty affirming stuff — stand up for the weak, protect the innocent, never betray the code of the schoolyard… which we all know is bullshit, but we operate on this level every day and won’t rat each other out, even when it’s the right thing to do. Homer’s worse-than-useless parenting advice is well-established in the series, even by this early point, and you have to love the way his memory shrugs when Bart is getting his ass kicked after trying to fight dirty. The good advice ultimately comes from the crazy guy, but what makes the whole thing work is teamwork, the willingness of a bunch of kids to band together and not take it anymore. I’ll come back to this idea later (there’s a point here, I promise), but from a values perspective this isn’t really bad at all. I’m not sure what got George H.W. Bush all worked up.