There is an obvious lack of homework.
Do you know where the majority of the first six films are set? Hogwarts. The school, for example. And you know what Ron, Harry, and Hermione nearly never do? Homework. You’d expect that a school as prestigious as Hogwarts would have a rigorous curriculum, and that homework would follow suit.
We understand that they don’t have much time to fill out worksheets while rescuing the world, but at the very least, have them do some math or anything. Oh, wait. Math is not taught at Hogwarts. Sigh.