if you get an occasional lousy feedback, don't worry about it. Everyone who buys and sells on ebay knows that there are crazies out there that ding your feedback for retribution or just for the h@ll of it.

Not to worry. Life goes on. The important feedback is in your head and on the faces of the people you meet, not in the ebay (or any other) bit-bucket, and certainly not when it comes from some anonymous trouble maker across the 'net from you.