Fully agree with Macros's reasoning here, firstly people typically want revenge because someting happened to them first, the next thing they resort to do is setlleing the score so to speak as a way of almost undoing what was origionally influcted.
However this is also like playing a game of tennis, and the revenge is like the ball passing constantly between the two balls. Now if you respond to whovever this is with a revenge spell, you will be sending out a negative ball to that person. And then they are more lickely to respond negitavly to you in return.
However, you choose to do nothing. Of course nothing will happen, but to make this better, you could forgive what happened? Maybe not nessiserily the other person, that too but mainly for yourself. Forgivness in which ever direction is a powerful emotion ans it will completley free you of your need to take revenge, revenge will only serve to disturb your peace of mind.