Self Deception
Self-deception is rampant in human affairs. And although too much self-deception is probably a bad thing, a little self-deception may be just what a person needs to get through the day. One should never underestimate the power of positive illusions. For example, psychological studies show that people who are overly optimistic about their own abilities often have enhanced motivation, which enables them to do better in the face of challenges than people with more realistic assessments of their own talents.
