There was once awhile I've read a book about "psychological of revenge", a very extreme, yet interesting content. I believe that there is no one who never ever think to revenge on something, even an animal does. The book was telling "the emotional of revenge cures spiritual wounds" which brought me to a reverse deliberation.
Historically, it happened among all of the living creatures. Can you imagine how the world will be if revenge was invalid? The wild animals born to possess high offensive power passively to protect their clan. This endless cycle has been played in all kind of communities for all time. There aren't end of elephants' attack news in India. Revenge and the anger against human are part of the factor.
This complex emotional transformed as time goes by. Children is educated for not being bully in school. It somehow becomes a strategy in office politics. You might doubt it could be a group influence but it is definitely an individual thoughts who affect the surrounding and evolve into group form. After all, to revenge because we are protecting and surviving. Frankly, the parties who are revenging gain the lesser pain and getting closer to their goal.
Have a good judge to position yourself in a healthy revenge nor a negative or extreme reputations while live under pressure. There is another kind of revenge extremely which inflict damage even death to innocents. This should be categorised as criminal, not the "psychological of revenge" anymore. We'd make the best of this complicated emotional to activate our motivation to the success way.
PLEASE DO NOT BLIND YOURSELF WITH THE THOUGHTS OF REVENGE!