Certain people, who are mostly pessimists, carry a negative mindset towards all events that transpire in their life. No matter how you tell them that things are better the way they occur, they fail to see the brighter side of events. Why doesn't positive thinking work for such people?

A pessimist will always see a half-filled glass of water as half empty. Give any task to them, and they may come up with all the faults as to why the task cannot be done, rather than actually doing it.

People who believe that there exists a perfect way or a formula to complete a certain task, and anything less or different than that perfect way is tantamount to failure, fail more often than succeed.

These people tend to see failure as a hurdle, rather than seeing it as a building block towards success.

People who believe that they got that special promotion or their desired job as a fluke, rather than due to their potential, often are of the belief that they don't deserve the good things in life.

This may stem from an inferiority complex, or a low self-esteem, that remain unattended from an early age, and could not be diagnosed.

There is a story in which a rich father gifts his pessimist son a valuable watch, to which the son becomes gloomy, and says, "the watch will require changing of the batteries to keep it running."

On the other hand, when he gives his optimistic son a room full of horse dung, he sees him digging through the manure using a shovel. Out of curiosity, the father asks him what he was doing. The son replies, "since there is so much horse manure, there's gotta be a horse in there somewhere."