We don't know as much about either as we think.
A growing body of experimental evidence suggests that, on the whole, we know significantly less about our friends, colleagues, and even spouses than we think we do. This lack of knowledge extends far beyond embarrassing game-show fodder - we’re often completely wrong about their likes and dislikes, their political beliefs, their tastes, their cherished values. We lowball the ethics of our co-workers; we overestimate how happy our husbands or wives are.“Our friends will surprise us much more than we would imagine,” says David Dunning, a psychology professor at Cornell University who has done influential research on how we perceive ourselves and others.
Although such blind spots might at first seem like a comment on the atomization of modern life, the shallowness of human connection in the age of bowling alone, psychologists say that these gaps might simply be an unavoidable product of the way human beings forge personal bonds. Even in close relationships, there are holes in what we know about each other, and we fill them with our own assumptions. [More]
Part of the reason for this lack of understanding - especially among men - is difficulty talking about personal topics and poor listening skills, I think. What I know is long-time friends in the past few months have surprised me with remarks or opinions I sure didn't see coming.
I think it's a good thing. It shows we're all still growing and changing, and maybe even listening a little better.