I'd suggest that if you genuinely don't understand this sort of social thing instinctively, then you're probably on the autism/aspergers spectrum then. I really wasn't trying to be offensive towards you or anything, I just probably forgot some extra caveats... Basically, this sort of social reasoning is (usually) hard wired into your (typical) human being, and has been since prehistory. But mental disorders like autism seem to mess up social perceptions and interactions, masking these instincts. Fortunately, in that case, I've found it's possible to work around the issue by simply researching what the natural instincts and drivers are for the typical human, hence my suggestion of referencing an anthropology textbook.
