Niceness? Nah

So people at school think that I'm just nice to be nice, but in all honesty I'm only nice to certain people, like I'll work with people to be friends but that's about it. I don't go out of my way to be friends with people or to be nice to them because why should I? Most people at this school don't like me in the first place, most of them are people below me so why should I care about them? My point is unless a person is nice to me first, I don't care about the way they feel or the way that I am affecting them. It doesn't bother me one bit to say that 100% I am a bitch and don't care about others and how they feel.