vengeance seems like a plausible response to a hurt. It suggests that when someone hurts you, you should give them their just dessert. In fact the concept of vengeance is so popular that it was running theme in most Asian movies back in the days. For instance, child witnesses the murder of his parents and grows to kill the murderers. The offended party is so wrapped up in seeking vengeance that nothing else matters! Vengeance becomes a consuming virus that drives the person until the goal is achieved.
David was no stranger to hurt. His life was constantly under threat so much he had a bounty placed on his head by Saul. However, when David got an opportunity to inflict hurt on his enemy he bowed out. Instead of killing his oppressor, he spared Saul's life. Read 1 Samuel 24. The natural inclination would have been to kill his enemy but David didn't. David's action is a precursor of what Jesus did on the cross of Calvary-extend forgiveness to God's enemies.
I am no stranger to hurts and betrayal but there is no room in my life for anger, bitterness, strife or retaliation (it has absolutely nothing to do with fact that I will be beaten to a pulp by the smallest opponent...I NO FIT FIGHT BIKO).
Life is too short to be consumed by negative emotions. Its a waste of energy. Your part in any toxic situation is to forgive and let God deal with the rest. Let God fight your battles. He is better equipped.