person: sir! SIR! WAIT!
guy: yes?
person: you forgot your copy of the receipt
*person that just handed guy the receipt has a big smile on his face*
guy (holding person's face): i left this receipt on purpose because i do not care about it
This happened to me. It was years ago at this point, but I’m pretty sure I feel obligated to take my copy of the receipt at all times now. Thanks, server-at-sushi-place-in-queens.