In our attempts to be able to successfully interact with unknown, we make a lot of assumptions about what that unknown is. We don't treat rocks, alarm clocks, and puppies the same way. Even in our interactions with people we're not sure what they're going to do, so we have to make assumptions about them. There are various ways one does this, a concrete way might be to base it off appearance and past experience with similarly-appearing people. A more abstract one would be to base one's predictions based on a person's star sign. While it might be insensitive and limited in how effective it can be to base assumptions off physical characteristics (e.g. "he's short and short people are quick to temper", "she's a redhead so she's got a fiery personality"), it's downright absurd to think that star sign has anything to do with personality type.
One stance that has utility is basing one's dealings off cultural norms where the person comes from. If the culture someone comes from has a strong focus on respect, it's generally going to be helpful to adhere to that when dealing with people from that culture. If a particular gesture is considered insulting in that culture, it helps to avoid it. It seems a fairly trivial observation these days that it helps to be aware of cultural differences than to be ignorant of them.
There is one concern I have with the cultural stance, and that's when it's over-applied. That instead of taking culture as one determining factor in an individual, it's taken as an over-arching determining factor. People cease to be intentional agents and instead become cultural ones; the cultural stance has shifted into creating the cultural entity. And if there's no other reason to reject it (and there are many), just consider the variation of personalities in our own culture.
It's a useful heuristic, but one that has the danger of being misapplied. We're all still people after all.