I don't get ppl who like to tear others down...?

I AM JUST SICK OF PEOPLE LIKE THAT! it's terrible! I have no clue why that do it, maybe they just have a need to make other people feel like crap....I don't get it at all...I treat everyone I know kindly even the low of the low....I just hate people like that..they usually don't say anything to me but they tear down some of my friends..