Why do some people derive pleasure from the misfortunes of those who are exceedingly blessed than they are?

Some people who are exceedingly blessed are envied by others who are less fortunate. This is the main reason why some people tend to feel happy for themselves when they see the fortunate people suffering. They feel vindicated. One example is the story of Cupid and Psyche. Venus, is less fortunate than Psyche because Psyche is lovelier than she is. Time came when Psyche had to suffer in Venus's hands. Venus felt extremely pleasured while punishing Psyche. She felt that they are already "quits". That is one reason why people tend to be happy for others' misfortunes. This feeling could not be avoided but we can stop it. At first it is like a benign tumor that if you ignore would turn into a malignant one. Meaning: once we start being happy for others' misfortune, we must control ourselves if we do not want to be worst.