The first time I moved to Germany (in 1999), I was absolutely flattened by culture shock. I hadn't spent that long learning the language, and thought everyone sounded so angry all the time. I couldn't figure out why shopkeepers always had to say hello and goodbye to everyone who came in, and I could not imagine why people were content going to 13 different specialty shops every day instead of one big all-in-one store. What a crazy place! What a waste of time! And then I started doing it too, and when it was just the way things were instead of some weird new requirement, it was fine. Yeah, American grocery stores freaked me out a little when I moved back the next year.
My most persistent culture-shock issue this time around has been the lack of personal space afforded in public. People step right in front of you to get on the bus, they'll stand unbearably close in line, and (most maddeningly) they get up early on the tram, walk over to the door, and loooooom over you until you let them stand closer to the door, even though you're still two blocks before the stop. Where do they have to be that's important enough to climb over a stranger to get there?
Interestingly enough, though, nobody talks to strangers on the tram. I may get jostled when the tram fills up, but I've never been asked what I'm listening to, or what I'm reading, or what my phone number is. My personal-space bubble may be small, but apparently it's soundproof. Liam is the exception to this rule: he says hi to people, particularly old ladies and babies, and is actually pretty good at making conversation ("I'm going to kindergarten. My socks have pirates on them!"). He's the quickest way to draw attention in public, and is pretty charming about it.