Simple answer you may think but really think about it. Why do people chose to be mean, chose to hurt others, chose to cause pain to others when it isn't necessary? What causes someone's psyche to go in that direction. I know the answer someone may give is the apple and the forbidden tree, Adam and Eve, blah blah blah... I get that is where sin resulted from but what causes someone to chose evil over good. What satisfaction does someone have being mean to people?