Which Self? Finding Safe and Common Ground

Whenever I am new to a situation, I always attempt to discern what sort of people I am around. I've become more aware of this since we have moved to America. It's as if I have to guess at the kind of people that they are, so that I can know which 'me' to put on. This might sound like I am being superficial, but honestly all of my different identities are truly me, just me in different contexts. For example, if I decide that the group of people I am around are Serbs, then I make a mental note of all of the social rules I have to follow: Never put your feet on top of a coffee table. You don't have to be punctual. Always leave a tiny bit of food on the plate, or a bit of drink left in the glass to let the host know that you are satisfied with what you have received, but do not wish to eat or drink any more. Show hospitality with food and drink, i tako dalje (etc). But the problem with living in America is that I do not know alot of the cultural rules. People didn't blatantly tell me that "Hi, how are you?" does not merit a 500 word response, and sometimes is not a question at all. And I had to total a car before I realised that police in America are generally not out to cause you harm, or demand bribes from you. So when I try to gage the cultural climate of the people I am around, I also try to observe any specific cultural rules that I can. This is generally why at a larger gathering I hardly ever go up to someone to introduce myself to them right away. If you talk to me, of course I will talk with you and engage in conversation, but for my part I would much rather listen than talk, as I get to hear about you, and try to get cues as to who I am allowed to be in your presence. Am I only allowed to be a person who is similar to you? Have you been out of the country so that I am allowed to talk about another place and you would not think me a prick? Have they had extensive or qualitative time overseas beyond tourism, that I might speak with them about cultural differences? Are they a military brat that I should refrain from mentioning any negative sentiment I might possess regarding America's handling of foreign affairs or America in general? This will help me to determine how much of which of myselves I am allowed to be. And the friendship does not have to be superficial at all. I have some friends who might know that I have lived overseas, but I am not sure. Nonetheless, we find common ground elsewhere, and have fun together. If I might emphasize something I've learned. Common ground does not always have to be on your turf. It could be on anything from 'Lord of the Rings' to philosophy, to a hobby, to what classes you have together. I've found that this common ground is more comfortable for the American, as it is more normal to find friends in these areas instead of finding common ground in experiences, like TCKs often do.