Language model fail

I'm just back to Scotland after two weeks in the US, and was getting on a bus into the city center. I stopped and asked the bus driver the ticket price, and heard " 2.10." I said "OK", and got my wallet out to pay. He looks at me like I'm an idiot and says forcefully "sit down!" Confused, I go sit down. After we arrived I asked if I should pay, and he looked at me like an idiot (again) and said that the bus is paid for by two other bigger bus companies as a connection, and is free to riders. My expectation of a price was so strong that I must have heard "sit down" as "2.10." Possibly also I was not quite acclimated back to the language variety this side of the pond.