What would I actually have done had I found someone who'd screwed me over stranded in the snow with a dead car battery? Of course I wouldn't have let them freeze in the snow. I would have helped them jumpstart their car. But after doing so I also would not let them just leave right away. I would insist on having a discussion about what happened the last time we had interacted so that I could get closure. If the person were my ex-best friend Melanie, for example, I would insist on answers as to why she didn't invite me to the wedding and why she cut me off, ignoring all my emails and phone calls. I am also a forgiving person so if she apologized and meant it sincerely and wanted to be friends again, I would forgive her and accept her Friend Request, so to speak.
Despite the popular misconception, revenge fantasies are not a symptom of an unhealthy mind but rather the mind's way of working through deep hurt. They are a way of owning your feelings (there will be an upcoming blog post on such owning soon). If anything, actually, people who have these fantasies are less likely to do something to hurt someone else. Don't believe me? Check out this article about it.