Separated by a common language

American woman, in informative mode: "Townhouses in England have more than one floor."
Me, puzzled: "But almost all houses in England have more than one floor -- we had to import a special foreign word for a single-storey house, 'bungalow'." (Also, a 'townhouse' is a *lot* grander than the sort of terraces we were talking about...)
American, getting angry: "Nothing I said has been wrong. The standard house in England has only *one* floor: the first floor on top of the ground floor." :-O

(I also discovered this week that 'slacks' in America means 'dress trousers' for a formal occasion, whereas in England it means the sort of informal trousers you might wear to go fishing or dig the garden but would never, ever wear to a dinner party... because they are, well, slack rather than fitted :-D)