Why on earth do I get bugged so easily???

Irritating people are never hard to find. I met ample number of them during my school days and college hasn't been any different. The problem with me is I get riled up too easily...if I am angry with a person it shows on my face. For my own sake I know I should learn to keep my not-so-friendly feelings in check but that is not so easy.
I hate people who think they are better than the rest-those who speak up in class just to flaunt their knowledge, I mean there is something known as Modesty. To a certain extent its fine but when someone tries to sound intelligent just for the sake of it, I feel like telling them to just Shut Up-anyway, invariably they end up making fools of themselves. Then there are the attention seekers who stoop to anything in order to get noticed. Watching them try their tactics-especially in front of teachers is embarassing, for me that is. They, on the other hand have no qualms at all.
I am well aware of the fact that I myself have qualities that might drive people crazy, but if I have any inkling of them I will consciously try to change. This tirade of mine can in all likelihood be considered arrogant- which I can be at times and which I know will not get me many brownie points. Strangers who see me walking on the road with my nose up in the air will consider me the biggest snob ever, but thats my way of keeping unwanted attention at bay. I am not trying to defend myself but people who get to know me will say otherwise, they realise that the person on the road is not the real me. Someone once called me dull because I don't show my emotions freely. I realise that is probably true but I didn't feel bad at all instead I felt like laughing because I like to have fun my own way-without making a complete buffoon of myself. If that makes me dull, fine by me.