Some people have such a strong sense of justice that when they get treated badly they end up stewing for years about it and in that way the person who wronged them manages to really ruin their life over the long term when otherwise they may not have done so.
I have a friend in the UK who is stewing about an incident she had this summer. She put it aside, more or less, for a few months but has now brought it up again. It's no wonder she brought it up again as one of the idiots was in her local paper for pretty serious animal abuse of a number of horses. Still I really worry about her in how she will stew and stew and "fixate" on these things. I don't know. To not do so would be to not have a strong sense of justice; a strong sense of morals; of right and wrong; so to dwell to some extent is the right thing to do. And certainly with this one person having been in paper now, it's understandable. But I really worry she's ruining her health going on about this. She has chronic health issues to begin with...
Many other people are doing this. There is a person in PA doing this. This person says they can't not do it. I would say one must try to believe in one's self. Don't just say, "oh well I have a mental disorder I can't help myself." Don't put yourself down!
My grandmother certainly did it. She was still stewing about things done to her 50 years previous. I remember a story about peeing the bed and being made to stand motionless in the cold until the pee froze on her. Another about a pig's ear with hair on it in her soup...
I've done it. When my scientific career was destroyed I certainly "fixated" upon the issue. And I did hurt my health. Another scientist there also was fired around the same time and he then got cancer and was dead within a year. I had a very mild case of the shingles which... So mild I ignored it but still the point was made to me as I don't normally get sick... Stewing isn't fun and it will even literally destroy your body. When these "evil" people wrong us, to the extent that we ruminate over it, they are "winning" so much more so.
So then, one can just forget. And perhaps so very very generally speaking, the dumber you are, the easier it is to forget.
Another method is to quit believing in the existence of 'evil' and thus to not feel anger.
Perhaps another way is to make it funny. Turn it to humor. This third way is more alien to me. I'd like to explore it further in the future. Is it possible to take my UK friend's account of the incident and find unexpected wrongs in it (humor) thus making it something a decent number of other people could actually stand to read?
It has been pointed out that for truly dark material, one must have humor.
So much of good, worthwhile literature, has been the result of people who clearly were dwelling to some extent on these things. I'd like to think though as opposed to it being a good thing that we just have to have these few people in "society" who are always miserable, (And maybe one out of every 500 or 50,000 or more actually accomplishes some nonlocally positive thing.) there would instead be a way to just put it on a very low simmer. Or something. I don't know.
I personally, maybe somewhat comically have flipped the saying, "Think Globally, Act Locally" on it's head. I want to ignore my own personal sufferings and find a way to reduce injustice globally... somehow! Other people need not carry it quite that far... but possibly instead of dwelling on their own probably unsolvable injustices, spend that time doing some other positive thing...
Instead of being like the windshield wiper inventor. His inventions were stolen by the automakers. There was a recent movie I guess making him out to be a hero for spending 40 years fighting them in court for stealing his invention. I think him a sorry person indeed. His life has been wasted. I had an invention stolen myself.
This isn't to say that one should just be totally passive. Not at all. Certainly my UK friend should write a complaint letter. In fact she should have just done that long ago. (In fact I've tried to help her do so...) That would be a good thing. But just write the letter. Don't spend half a year stewing and stewing about it. Don't ruin your health over it. :(