Some peoples real self is worse then their pretending. :/
obviously they don't like their true selfs or care too much what others would say if they do
I think its because when people stop caring -actually stop caring- what their peers think of them, they tend to slip into destructive behavior. Someone running a marathon or working in a homeless shelter may tell you they don't care what others think of them, but they are really saying that they are pretty confident that someone is impressed.
lack of confidence
Maybe. THere might be more reasons, like low self-esteem.