I hated school because it was boring. I didn't exactly hate the teachers, but I didn't have any concept that they might want to teach something.

Back when I was in highschool, a friend and I were accidentally sorted into a general level course, when by rights we should have been put in an AP-level course. Neither of us ever really got anything out of the teacher's lectures, and were able to ace the tests purely on knowledge gained from reading the textbook; consequently, we were bored out of our minds in class, and amused ourselves by competing to lure the teacher off on increasingly interesting and increasingly irrelevant tangents. A side result of this was that the other students, who actually needed a the hear the subject explained by a teacher, got shafted. I should note, however, that neither of us had any real animosity towards the teacher or the students -- in fact, we absolutely adored the teacher; rather than being a malicious attempt to disrupt the class, we saw it as merely a friendly game between the two of us that happened to negatively effect other people's learning of the material -- a consequence that we were indifferent towards.