This may be a very subjective view of the situation and feel free to present other viewpoints as well. I was reading some very cringeworthy FR's and also reflecting on my personal experiences with rejection in clubs and it struck me why I felt so terrible about being rejected.

In most societies, when we meet strangers, especially when they approach with good intentions, we are open and civil with our reactions. If we aren't interested, or don't have the time, we make excuses (I gotta leave, but nice meeting you). Fast forward to clubs where many times the rejections are brutal (being ignored, friend grabbing the girl and both walking away without speaking, giving looks of utter disgust etc.) and this is completely contradictory to the kind of reactions that we normally expect.

For me, this triggers intense dislike for the other person, and I do want to see them punished in some way. My personal reaction has just been to ignore them completely, but this feels rather insufficeint. And then if you see your target having fun with others it makes the feeling even worse. The feeling basically is that they should be punished for their behavior but are not and that makes me unhappy and it feels like I have no control of the situation.

I know this stuff sounds very evil. Of course I wouldn't physically hurt anyone and I've never even been in a fight. But pondering over why rejection feels so bad, this seems to be the root cause for me. I don't know what the solution is; putting it out there in case others feel the same.