“Enjoy your game”

Many many years ago, (before we had children, even) we had friends over for a day of GURPS IOU. At one point we ordered pizza, and as the delivery guy left he gave us a big knowing smile and said “Enjoy your game!” At the time, I thought “Wow, that’s amazing. How did he know we were gamers?!” It was only much later that I realized what he actually meant.