Sure, because getting to know people takes a lot of time and effort and opportunity. OTOH, seeing what they wear or drive or where they live takes a few seconds. Usually, the "knowing process" moves along over time in gradual steps. Doesn't it?
Story
I met a guy in the woodshop in early January. He was my age, pleasant, and we had a long convo about the various guitars we owned and would like to own. He suggested we meetup, play some guitar together. Yeah sure, why not?
A couple weeks later he arrives at my house. He brought his music, I had mine. We sort of alternated playing our music - joining in with the other if we knew the piece - very informal. It seemed to be fun and casual, but he seemed a bit formal, or tight. Then, as he's leaving he turns at the door, and says flatly to me, "Well, of all the times I have played guitar with other people....this has been the most recent," and walks to his car.
Uh, ok then.