I think there are one or two clues in what you have already told us.....if you will forgive me for stating what might seem obvious....sitting with your colleagues for coffee is an easy way to get to know them if you listen rather than talk....not to do so when you are new may seem stand-offish.Asking people their qualifications may also be read as you trying to compare if yours are better than theirs or even, questioning their right to be there. You mention that people think you are strange, how do you know that or why do you think that? Where have you been new before and how did you fit in there?