Because it's such a powerful motivator, we often have to be talked out of revenge.
When we're feeling bitter, it's often our first instinct to want to make the person who wronged us feel as miserable as we do. And while it's definitely possible for a stranger to get under our skin enough to inspire this response, we'll usually find that our most tempting targets are the ones we have a long history with.
But regardless of who pissed us off, we'll often be told that getting them back will end up leaving us with less satisfaction than we think it will. Not to mention, the pain we felt won't really go away because we'll have just replaced it with regret.
Yet while there are plenty of cases where that's exactly how a revenge plot turned out, some will find such a clever way of achieving it that they still can't help but feel like it was worth it.