He abused me, he beat me, he defeated me, he robbed me – in those who harbor such thoughts hatred will never cease.
This verse, at the very beginning of the Dharmapada, speaks of the very simple truth that if we bring to mind our wrongs and nourish our hurt and anger, we make ourselves miserable. This verse caught my attention a long time ago, because that is exactly what the mind does--it repeats the list of the wrongs someone else has done to us: “He did this. She did that.” followed by your favorite four-letter word for people you dislike. Like a bulldog with a bone, the mind chews on hurtful events over and over again.
Another Buddhist scripture speaks of revenge being like trying to throw a hot coal at an enemy, we burn ourselves before we even have a chance to hurt anyone else. Someone who says “I will never forgive!” is really saying that they will nurse their grudge internally and turn it around and around in their mind, making themselves feel terrible, while the object of their hatred is untouched – this is assuming one is not planning to break the law by doing violence, which leads to its own cycle of suffering.
Now, I'm not so perfect that I've never nursed a grievance. There's a huge amount of energy in anger and you feel like you're going to explode if you don't do something with it. I tend to talk about it until I run myself to a stop. During domestic arguments, I do housework --- the place is never so clean as when I'm rolling on a big internal rant. Ideally, one should use that energy to resolve that situation. I had something happen at work that was unjust, and I used that anger to solve the problem in a professional way, then poof! Anger all gone. Sometimes, I find what's under the anger is essentially anxiety – and knowing that doesn't make it go away necessarily, but it does give me a tool to fight it with. Because., as the Buddha makes clear, it's your own anger that's the real enemy, not the person you're raging about.
It's hard to let go. I sometimes hang on to the illusion that if I can only just explain how they hurt me, they'd understand and admit they were wrong. And let's be honest with ourselves: There is something pleasurable about the idea that we can have the last word and put someone in their place. We fantasize about it. I think that the next time a doctor asks me if I eat French fries when I've come in to have an ingrown toenail treated, I will tell him exactly what I think of him and his stereotyping, and I will stomp out of his office, numbed toe and all! (And I've eaten French fries less than a half-dozen times in the last ten years. Bastard!) Anyway, it's a very satisfying picture to think that you can let 'em have it and leave them speechless as you storm out the door.
But that usually doesn't happen. People aren't “put in their place”; they just defend and justify themselves, and do their best to put you in the wrong. The more you try it, the worse the conflict becomes. The more you justify yourself, the more ammunition you give to someone who wants to put you down. In my experience, the only way to really end any conflict is absence and stubborn silence. It takes two to fight. Nobody can keep a fight going by themselves, except in their own minds.
Probably the best tool in your arsenal for that mental fight is the practice of metta (loving-kindness) meditation. It really is the opposite of the “He wronged me” rant quoted from the Dharmapada. Instead what you do is say phrases like “May he be happy. May he be healthy. May he be safe. May he be at peace.” You can google metta and find a wide variation on the theme, but the basic idea is that we start with wishing ourselves well, then those who are close to us, then in ever-widening circles until we embrace the entire world with loving-kindness. But included in this practice are those wishes for those who “we have difficulty loving” or “a person that we find difficult”. If I stop and think about it, I don't really want anything bad to happen to a person who has made me angry. What I want, mostly, is for them to leave me alone – and if I keep stewing about what they've done, it's just a way of keeping them in my life. Ideally, one should be able to endure obnoxious people and still wish them well, but I'm not that saintly yet. One step at a time. :-)