Apparently this arises for me occasionally out of an offended sense of justice. Or just a desire to see others suffer.
I'm unlikely to do anything much about it, but if someone has really hurt my feelings, offended me, wronged me in an extremely serious way (which probably involved a lot of ongoing unacceptable behaviour), it drives me nuts if they then go on their merry way and seem to be perfectly happy and getting everything they've always wanted out of life. (If they have managed to offend me that much there is usually strong evidence to suggest that they have managed to do the same to others, so it might not be just about me.)
There's part of me that would just like to see them get zapped by karma or something similar. Some people say to me that people who behave really badly will always reap what they sow, but sometimes it takes time.
Do you have any comments on your experience with these type of feelings, their validity, how you can defuse them etc?
Seriously, if I were a really vengeful person and willing to do something about it, there are a few people I've known who I might have done something really nasty to by now!