One of Peter De Vries's comic novels has a character who accumulates Briticisms. As I recall, he orders shrimp cocktail as a "starter," refers to a friend "called" James (instead of "named" -- that's a subtle one), and fills his car with "petrol" for the ride home. Eventually, he winds up in hospital. De Vries's conceit, delicious as it was, was an exaggeration. Generally a Yank can get away with at most one such locution in his or her active vocabulary, for example the person I know who likes to refer to his time "at university," the university in question...