It's probably not a surprise that Finns have a negative attitude towards groups, especially if you have seen this picture of a bus stop in Finland:
I think it's just wise to stand outside of the stabbing distance...
One American thing Finns ha-- umm... are not very fond of, is that a stranger might start a conversation with you in a grocery store. Stranger in this context is somebody you are not best friends with. We want to buy our groceries alone! (And wait for the bus alone.)
Finns consider "not disturbing people" one of the greatest virtues, and that's why we have such a restrictive social code regarding when it's okay to start a conversation (or even say hello). In many situations we assume that others want to be left alone and yet we secretly hope that somebody would socialize with us. So tragic.
I'm slowly getting used to the question "How are you doing" / "Wie geht's?" in the non-literal sense. For example, at work I try to answer with a cheerful "Oh, pretty good", as instructed by an American colleague. But I think I always have a stupid facial expression when I say it, so my colleagues probably think I'm crazy.
One very confusing situation is when a doctor greets me with this question, so... what am I supposed to answer? It feels so stupid to say I'm doing well - obviously I'm not doing well since I need to see a doctor!