why hatred exist?

I knew many friends around me who hatred so many things around them. I felt so tense with the situation and sometimes make me blast somehow. Just imagine we're living in this world together then at the same time some people are just hated you so much. They are around you and anytime they will make you depress just because they will try so hard to make you feel uncomfortable. It could be by using bad words or gestures. But why? I don't understand it at all because we are having the same features,but at the same time you hate that person. so unethical!  People involve in war or fight in which they are killing and hurting the same features as they are. Oh my what happen to this world. Weird and funny at the same time. Although hatred exist, but I think caring and loving people still around only that the positive one usually covered by negative aura around us.Please people don't make your life miserable. Enjoy it so you will find the world full of excitement. Helping others make your life more meaningful and making people happy much more worth than making them cry. The world is the place to do good deeds before you die. There's no way to come back to regret what you did before. So try to be rational be nice and make this world as peaceful as possible, so there will be no more absurd characters that everybody afraid of. Peace and harmony will cover the destruction  human created in this world.