Here is a funny little story about how negative beliefs can affect us:

There was this troubled man that believed that he was a corpse. He would say, “I am a corpse, I am dead, I am not alive.” His doctor got this idea and said, “Do corpses bleed?” The man replied, “No, corpses don’t bleed because they are dead.” The doctor then said, “If I take a needle and prick your finger, and you bleed, would you believe that you are not a corpse?” The man goes, “Okay.” The doctor then pricked his finger, and the man started bleeding. The man exclaimed, “Oh my God! Corpses do bleed!”

The point here is that when you have a strong negative image of yourself, even evidence can’t change your own reality. Likewise, most successful people have such a strong positive image of themselves that no matter how harsh reality is, they find a way to succeed. It is important for us to have a healthy attitude. Our reality is really what we make of it.