@Glenng @Niralam He's perfectly normal, as far as I can judge. He's a serious student trying his best and getting worried about his impending university entrance exams, like he should, as a third year (or late second year in the beginning of the manga). Satou is a poor student who even slowed down the classes, which he would view as a direct offense to his own goals and values. Of course he would have a dim view of her. At the end of the day, aside from delinquents, a student's primary job is to study, so anything that goes against it gives an initial negative impression in the long run, even if most students wouldn't mind a sudden free day, for example. Well, that was all she was to him when the story began, but naturally later he began to see her as a person, not just as a poor student. That's how it goes.
Personally, I have always thought it doesn't matter what's going on inside a person's head. Their actions are all that should matter for the rest of the world.