By the time we reach puberty we start to compare ourselves with other people. Our inner critical voice talks to us and tells us we are too tall, too short, too fat, too thin, our hair is too curly or to straight. We will never be good enough. With this, our self-esteem takes a nose dive and we don't like ourselves. There is a direct correlation between high self esteem and people who become high achievers, top sales people and top mangers.
Most people programme themselves to fail.
It's just as easy to programme yourself to succeed.