[wharvle]

It's got nothing on medical billing. Seemingly random bills from entities you may never have heard of showing up months later even when you paid a shitload (thousands) up-front.

[EDIT] Oh and they may not put enough info on the bill to figure out WTF it's even for, without calling them. It'll have some uselessly-generic single-line item for what was probably multiple things, but you'll have to spend an hour on hold to find out what you're supposed to be paying for.