When exiting a restaurant

Let us suppose (for the sake of argument) that you have just had a nice supper at a sit-down restaurant. You are just leaving and one of their helpers holds the door open and says:
"Thank you for coming. Have a nice night."
The usual response is something like "Thanks, you too."
Oh, that's sweet. But it's really boring.

Here is just one way to spice it up- respond with "Thank you. Uh, Sorry about the mess." The poor man will be flabbergasted. When he asks, "what mess?" just answer "You'll see."

The trick is to be very vague. Don't give any details like in the bathroom, underneath my table, in my napkin, on the floor etc. Leave it completely open to his imagination. He may even abandon his post at the door and go looking for this elusive mess. It's pretty ironical, because he's the only mess you've left.

Try it. They love it.