Yes, No, Maybe So

Today, I went to Olympia and hung out with some friends. We had fun. We went to an ice cream place. I ordered a chocolate milkshake. The worker guy asked if I wanted whip cream on it. I said yes. He thought I said no. He said "no?", and I said yes. He said "yes-no" or "no-yes". It was rather confusing, and in the end, I didn't end up with any whip cream. The shake was still good though.