These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Billy Madison
Big Lipped Alligator Moment: There is a solitary musical sequence in the middle of the movie containing several of the film's characters.
Additionally, the "Schlopppy Joes" scene. Even with vaguely dramatic music playing in the background, it adds nothing to the plot.
Family-Unfriendly Aesop: Go ahead and teach grade-school kids that peeing your pants is cool! Billy does this to keep one boy from being mocked. The class learns the lesson well, and it's treated as a good thing. Veronica even praises Billy for it, which makes her about the worst schoolteacher in existence.
She's pretty much shown to be a terrible person all around, it's one of the reasons they're so suited for each other.
Technically the aesop was about making people who were going through a rough time feel better. It wasn't about peeing your pants, it was about "do you react to someone being embarrassed by saving him from embarrassment, or by humiliating him further"? Billy chose the former when he had an opportunity to do the latter; that is what the teacher is praising him for. It was about the principle of the thing, not the thing itself.
Memetic Mutation: Pretty much every line in the film. If you grew up in The Nineties, you can probably quote this film line-for-line. Special mentions go to "O'Doyle Rules!" "Shampoo is better/No, conditioner is better," "Nudie magazine day" and, of course, the whole "I award you no points and may God have mercy on your soul" monologue.
The latter became popular to put after Sarah Palin quotes during the 2008 presidential election.
This troper is convinced that there is a particular demographic who will, upon hearing the word "chlorophyll", will either reply, or think, "Chlorophyll? More like BOROPHYLL."
Strawman Has a Point: Eric is a Corrupt Corporate Executive and sleazy Jerk Ass who merely wants to run Madison Hotels. However, he is right when he points out that the company's fifty-thousand employees are not likely to have jobs for very long if the president makes his drunkard son (who only graduated because his father bribed his teachers) president of the company. Note, though, that before Billy strikes a deal to graduate legitimately, this actually does temporarily convince Billy's father to hand the reins over to Eric. It's also noteworthy that, after some Character Development, Billy himself concludes that he's not cut out for the management of a large company and turns it over to Carl, who is both competent and not a Jerkass.