Didn't answer the cab question because I've never been in a cab before. (Hicksville, I lives in it.) And I don't usually get anything more complicated than plain old coffee or tea at actual coffeeshops, so yep, change. Otherwise it's 20% across the board.

THIS IS SORT OF EMBARRASSING, but I have to carry around a little card that lists 15% and 20% of various dollar amounts because I can't do math in my head. XD;;