Another notion that I cannot shake.
I have this idea that, whatever else is or is not present in a picture of a person, you can instantly tell whether the photographer liked, disliked, or was neutral toward the subject. At least in that moment.
In Let Us Now Praise Famous Men as I have noted in the past, it is instantly apparent that Walker Evans liked one of the families, and disliked the others. Amusingly, the one he liked was the one most despised by James Agee (who mostly liked the other families because he was convinced that all the women and girls wanted to have sex with him -- Agee was appalling).
Sally Mann, interestingly, strikes me as having a quite neutral attitude to her kids as she photographs them. She obviously loves her kids to bits, but somehow in that moment she seems quite distant. Not disdainful, but neutral.
Arbus seems to actively dislike her subjects.
And so on.
It's a sort of crazy notion, I cannot at all see what the mechanism would be, and yet, it seems perfectly clear to me.