shibboleths

What I'm going to say sounds more clever in my head than it will here, I swear. Along with my lengthy musings on habit lately, I've been thinking about shibboleths. Yesterday, some friendly man greeted me with enthusiasm, apologizing because he hadn't realized I was here, and would have said hi earlier. Then a different man yesterday said hello in the way that you do when you think you know someone, but can't place them.
Here's the thing: I don't know either of them! Of course I don't, how could I? I don't live here. But I looked as though I belonged in this building with the archives. My glasses, my messenger bag slung crosswise across me, my loafers, the colors I was wearing all made me look like someone who belonged there.
I think there must be loads of these little shibboleths that indicate inclusion in whatever group you're in, or indicate that someone belongs where they are. I just happened to do well at whatever shibboleth bingo was in these guys' heads yesterday.
Anyway, as I said, I think there's an interesting (if not startlingly original) idea somewhere in here, but I don't know that I've managed to convey it here.