Self-deception

"Self-deception has been uncovered in a wide range of situations, says Robert L. Trivers, an evolutionary biologist at Rutgers University who has studied the phenomenon. Before the Challenger explosion, for example, NASA engineers noticed that one of the O-rings on the space shuttle had been eaten a third of the way through. Since the shuttle had flown and returned to Earth, the engineers concluded that it was not a problem. Surveys show that four in five high school seniors believe they have exceptional leadership ability, and nearly every single professor in the country believes he or she is above average."