Talking with a friend who was born and raised in Japan, but moved to the US after serving as a stewardess on Japan Airlines, and ultimately becoming an interpreter at the UN....
She still has trouble with American colloquialisms... such as "play it by ear" or "flying by the seat of your pants".
But she said her major faux pas was at her first job...
She came in one morning, all cheery, and announced, "Good morning! Today is Wednesday. Wednesday is the day for humping" ;-)
...Jim Thompson