Optimism

If optimism is not hard-wired into the brain as an evolutionary trait, humans will not be able to go beyond limits especially during the faces of danger. The world will be much more dull and pessimistic as time passes. When optimism goes out of reach, fail will obviously be an option to all situation which involves a face of trouble. From what I heard, optimism is somehow connected to creativity, without ideas to continue the chain of creativity, the chain would break and the world would have not much creativity.

The world will be in chaos if people do not have the optimism requirements. The problem is that if a person is pessimistic, he would most probably be unhappy all his life, bring it on to a larger scle of 6 billion people and you would find the entire world filled with chaos. One common scenario are the "creation" of burglars.