Ha! I can better that one; 17or 18 years ago I became the owner of an $1,800 hole. I'd had a root canal/post and crown done on a back tooth in the late 1980's and it went quite badly wrong, ending with lot of pain and 23 stitches following a surgical extraction (which I was never charged for so I can only assume they stuffed it up). I really didn't want to go down that route again, but my (new) dentist was so nice; he convinced me that I should try to save it and that I'd just been really, really unlucky and lightning doesn't strike twice and anyway, he wasn't going to attempt to do it himself - he knew a top rate orthodontist, and he wouldn't have gotten to be in a 30th floor office in Collins Street if he wasn't really, really good at what he did. I should have listened to the thunder that was starting to rumble.
A few weeks later when I went to my GP in a very bad way, having lost 20kg (even if I had had an appetite I physically couldn't eat) she looked at the 10 day course of antibiotics Mr Top End of Town had given me (TWICE) and, shaking her head, said 'Was he an older man? (Nope, younger than me). We don't use those for this kind of infection any more'.