I remember once that my husband and I were traveling to the USA, we were in Miami Beach.
One day we went to Fort Lauderdale and stopped to refuel, but in the USA there is no one to help with gas stations, you have to do it yourself.
We were trying to find out how it worked when an employee approached and my husband started saying "I'm not an American ..." and the man said "no?" and he started laughing and I started laughing too, my husband frowned, he didn't like it very much, but then he laughed too and the man helped us with the bomb.
During the trip we laughed a lot and he thought he was stupid for telling an American that he was not an American.