True story from our dim-witted criminals department:

A man walked into a convenience store, put a $20 bill on the counter and asked for change. When the clerk opened the drawer, the man pulled a gun and asked for all the cash in the register.

The man took the cash from the clerk and fled, leaving his $20 bill on the counter.

So how much did he get from the drawer?

Fifteen bucks.

Go figure.