Opposite problem for me — I came from a fairly reserved culture and found the local friendliness almost overwhelming at first, strangers striking up full conversations at the bus stop. Took months to relax into it.
Where I'm from you chat to everyone — the cashier, the person in the lift, strangers at a bus stop. Here that same friendliness gets me confused looks, like I've broken some rule. But then people are incredibly warm once you're actually introduced. Did anyone else have to relearn the whole small-talk rulebook?