In a high school AU where Stuart and Paul somehow take at the very least one class together, I bet Paul would absolutely loathe Stu bc he never fucking pays attention or does anything, and he still gets decent grades.
Stu probably spends most of his classes sketching away on the corners of his books or straight up skipping 'em, and it's absolutely nobody's problem but himself's, and still Paul's frustrated by his existence.
Don't wanna turn this into a cliché where they gotta work on an assignment together and end up falling in love, Paul just hates him from afar. Stuart actually admires Paul for being so smart and dedicated to schoolwork, but he hates him back because he's such a teachers' pet.
They're both pretentious teenagers who don't speak to each other but still manage to hate each other, that's it.