The vendor used several clever rhymes when he was standing at the portal. He was shouting things like "Don't leave your seat, I've got you a treat!" My friend, who was sitting two seats down from me, was impressed with his salesmanship and decided to buy a (four dollar) bottle of water from him.
I passed him her $5 bill and he pocketed the extra dollar. My friend said, "Ask him how much that water is?" So, I asked him, "Is that water $4 or $5?" To his credit, he begrudgingly admitted that it was indeed $4 and then simply stared at me. I then asked, "Can she have her extra dollar back?" That's when we all became "a bunch o' no good, cheapskate, rednecks"...and the mayhem ensued.
Some other words were exchanged, and he didn't make it back up to our section.