Spoken like a person who's never gotten theirs. Im of a differing opinion on both counts.
I admit I'm not a vengeful person. I think people that do bad things are very troubled and unhappy anyway. I do believe in fighting for what is right and what is yours, but that is different thank obsessing on revenge. It takes over your life and that is no good for you or the others around you.
Perhaps what you call obsessing over revenge; others call fighting for what they believe in. If there were a justice driven deity, delivering justice, such things wouldnt be neccessary. However as it stands now; the only justice one gets on this earth is the justice they make themselves.
If it makes you a better person, I stand corrected. We all have different goals.
Its not about becoming a better person. Its about balance. If a misdeed goes unanswered it only enboldens the miscreant to continue down that path. Then the next time they wrong someone; it only perpetuates the negativity. Break the cycle, break the habit, break them if need be. But never let a slight go unanswered.
It's one thing to answer back, another thing to get revenge for "perceived" wrong doing.
For example, your spouse cheats on you and leaves you. Revenge situation or no?
Your boss fires you without cause. Revenge situation or no?
Someone maliciously harms your spouse or child? Revenge situation or no?
In the first two, I would choose to move on. I agree you should not "enable" bad behavior, however, they are adults, and I would not want a partner or boss that is like that anyway. No likely they will change, you may only ruin their lives.
In the last scenario, well, it would be hard for me not to seek revenge because it's more violent and it's being done to someone I love, not myself.