Okay, finally got to the end of the thread. Now I can include mine.
First is a local pizza place. We ordered from there frequently. They had the best cheesesteaks, and really good pizza, and their prices were reasonable. Too bad the owners weren't.. It was the day after an order, and we get a phone call from them. They said we gave their driver a counterfeit $20 bill, and we could either give them $20 to make up for it, or they could go to the police to get it. Well, see, we don't get $20 bills. The local ATM dispenses $10 bills only, and there's no way we would have had anything larger. But, I panicked, and let them pressure me into giving them $20 I really didn't have. Last time I ever ordered from there. Given the frequency we ordered, and the amount of time it's been, I estimate at least $1000 in lost sales.
EBGames lost my business back when they were Electronics Boutique. They had a policy, they would refund as long as you had the original materials, as long as it was within seven days, even on PC games (this was very much a long while ago). Well, I bought a copy of Windows 95 (on floppies!) from there and get it home... dang thing won't install. Gets to disk 4 of 13, and borks. We took it back, asked for an exchange (thinking it might be the disc), get a new copy, and try again. Nope, same problem. So we take it back, ask for a refund, since I'm not paying for an OS I can't even install. The manager, as he's writing out the return form in front of us, dictates what he's writing as he's writing it: "Reason for return... did not like'. Since I don't appreciate being called a liar, I took my refund, left the store, and never went back.