Contest prizes and art trades - should I let it go?

[growly.livejournal.com]

How serious do you consider it if someone doesn't make you a prize you won in a contest?

What about art trades, how far should you pursue someone about a piece owed?

I've sort of given up about some things I'm owed, after waiting five years for one, and two years for another. I think it might be overkill and whiny to post about these things I'm owed, because no physical money was involved (except postage and shipping materials on the trade). And I don't want to make these people mad at me, either. One of the people I'm on good terms with. :/ Maybe that's a poor reason to not to post about somebody, but I hate burning bridges.

Should I just let it go and forget about it completely, or do you think I need to continue to ask about my art?