I had a few odd ones when I was actively selling.
One guy bought a couple $1 cards. After about two weeks I sent a gentle reminder. Along the lines of "maybe it slipped through the cracks, or you got busy, Just let me know if you've sent the payment." Next day I get an email saying it was from his girlfriend and that he'd been drunk that friday and being new to Ebay bid on some enormous ammount of cheap cards. And surprise, he won enough to be more than what he made in a month
So I checked his purchases. Yep, around 1200 items won, none over $5. Total bill without shipping probably around 4000. I told them to pay me whenever they could. To my surprise I had a check in about a week. AND it cleared.
There were the usual bunch of "where's my card" questions, my favorite sent 30 minutes after he won and about 3 days before he paid.
I had to wait a couple hours before answering that one.
And at least one really tough one. I sold a Naval academy souvenir mug but didn't get paid. (VERY strange for any of the service academies, I've sent out a few West Point things before payment just because the buyer was a graduate. Never a problem.) Anyway, after about a month I got an email from a family member saying they were trying to sort out what he'd bought and what had or hadn't been paid for. Apparently he had cancer and had gone into the hospital for what was likely the last time. I offered to send it out for free but they asked me not to. I told them that any payments would be returned or simply not cashed if it was a check and they were ok with that.
I still have it here somewhere. It's odd, but I get a wierd feeling whenever I think of selling it. Not spooky wierd, just a "I just don't want to sell it" sort of thing even though it's pretty far outside what I think of as collection rather than "inventory".
Steve B