For me, its about forgiveness and an attitude of the heart. When people mistreat us, we have to be the bigger person. Like you state - getting even leads nowhere. Whats that saying - if we go by eye for an eye and tooth for a tooth, sooner or later everyone will be eyeless and toothless.
One small comfort, for those who are vengeance inclined - the Bible also says that:
"If your enemy is hungry, give him bread to eat, and if he is thirsty, give him water to drink for you will heap burning coals on his head, and the LORD will reward you." Proverbs 25:21-22