Gahh.. This isn't really about a bad trade, but it still has to do with trading, so...
So I see this person who has a list of the pets they need in their sig. I notice I have extras of most of them, more specifically a rare bunny. So I send em a trade, giving the bunny, asking for nothing in return. Leave no message. They accept, no message, nothing. And... I dunno. Just sorta ticked me off. I gift a complete stranger with a rare pet I could probably auction for a lot, and I don't even get a "thank you". Gawd.