Different kinds of Discrimination in school

People experience different types of discrimination. People discriminate people base on their wealth, Intelligence, skin colour, height, Language, looking and etc.. Why do these things happen? Why people think that they are more superior than other people? Me, as my personal view, people discriminate people because of their surroundings, mostly effected by others thought. Its like they do that's why I do as well. But for kind harted (like Jerry! LOL) can change the the thoughts and prove them that their thoughts aren't right at all. But of course I we can't force them to change their thoughts because they also have the right to think the way they want. Some great thinkers had sited that All Men were born to be free and have rights. In school, students usually discriminate their friends by the colour, wealth and intelligence. Well discriminating by colour is the way people commonly do. A great example for the discrimination base on a student's intelligence is when friends don't want to listen to a friend's thought just because he/she doesnt really get high grades in his/ her academic achievements. Well everyone agrees that discrimination is not a good way of treating other people, but, as people say its hard to remove or its all most impossible to remove, what we have to do is, just put up with this condition.