I learn and relearn that whenever I'm in the U.S. for work.
Here, we hug and kiss the cheeks of anyone we know well enough to address by their first name – and if we use first names, there's no "sir" and "ma'am" (en français, on se tutoie et on ne se vouvoie pas même le grand patron). Even at work, it isn't weird to find something good about a person's looks or outfit to offer as a compliment (e.g., "That's a great dress!"), and lunch often involves a little drink (a beer or a glass of wine). Sex on TV is 13 ans+ (roughly PG or 14+) unless graphic, while it's violence, especially with guns, that's 16 ans+ or 18 ans+; as a result, you'd never talk about firearms, but PG innuendo and flirting is acceptable outside of a courtroom or a church. Speaking of which, most people don't go to church – they're "Christmas Catholics."
Then I get to the U.S., where I have to remember to stand at an awkward physical distance, "sir" and "ma'am" people, not notice looks, drink "iced tea" with lunch, never even think about flirting, not recoil when somebody shows off their new .45 at work (!), and respect all kinds of intense Protestant values (work colleagues I can't be chummy with will nevertheless think I want to go to church with them on a Sunday). To me, that's very, very uptight and prudish. I find it suffocating.