Yesterday, I was chatting to F and she introduced us to the only other black person in the room, who had been sitting next to her. I asked whether he was her partner and he immediately reacted.
Not being able to read minds, I assumed he reacted because he believed I put them together just because they were the only two black people in the room, like N couldn't possibly have more than 1 non-white friend. I don't know, but I tried hard to make up the lost ground then.
Now I realise it's possible that he reacted because there is an obvious age difference or because he's not attracted to her - or because he's very attracted... or something else.
Sometimes I think I over-racialize the world, that I read things too much in those terms.