A very tired doctor walks into a bank branch after an all night shift.
He gets his cheque book out and tries to write a cheque.
After a short while, he realises that he has not got his normal pen but is trying to write with a rectal thermometer.
Realising his mistake, he sighs: "Well, that’s great … that’s just great … typical …"
The teller asks him what's wrong and, without missing a beat, the doctor replies: "Some asshole has taken my pen."