I have noticed this as well in myself during some of my classes, I think the best way to combat it, at least for me is to not focus on it or other people, like how they act or however stupid their answers are, and try to keep an open mind. It may not work for everyone, but i feel it works for me. Another thing is to just keep quiet, you learn more from listening than talking, and you can't sound stuck up if you don't talk, just do your work, as you are there to learn, not goof off, get in trouble, make friends or be socially popular. But to combat arrogance, just find how you get to that point and combat it from there. Basic step though, is to be nice to everyone, even those you hate, it helps a lot later on, as teachers, co-worker, and bosses will be more likely to write you recommendations, and i think it helps to be a better person.