I'm generally comfortable with endorsing Culture A, but the whole "teasing and jostling each other for fun" is something that can definitely backfire. It makes the most sense as a strategic signal of common values, but it should definitely be avoided when interacting with those who are plausibly outsiders to the culture. (People can nonetheless be gradually educated into it by expressing praise when the inevitable social conflicts are resolved quickly and easily, or even when they start dishing out some good-natured ribbing of their own.)