For a few months now I've had a debt collector calling me on my work phone insisting that I owe them money for a Ford van that I bought. Trouble is, I don't buy Fords because I think they suck. Turns out, it was the employee who had the phone before me (and who got fired) who bought the van.
The debt collector is now telling me "well this is the phone number we have for the account, you're responsible for the debt."
If I were psychotic, I'd kill someone and mail the murder weapon to the collection agent. After all, if he has it, he's responsible for what it was used for in the past, right?