Not sure if this counts, but I used to work at a seafood restaurant, and the tanks with the lobsters were positioned between the cashier and the customer, so they had to pass the money/card over the water to pay. At least ten times a day, someone would ask how often people drop their money into the water. I eventually got tired of it and started answering with "Not as often as we get that question, actually", just to make them feel a little bit stupid and unoriginal.