(major snippage of a really good post)
Of all my time in Japan, all the great things and not so great things I learned, one thing struck me hard:
I'm not Japanese. That's a good thing. I like being American. I like how we do things. I like Japanese culture, and I have Japanese friends, but I would feel utterly trapped in their culture if I felt I had to take on all of their social attributes to be "doing it right".
That whole "giri" (obligation - sort of; duty - sort of) thing, and culturally knowing what you can/can't do, should/shouldn't do. Ranges from which words to use in a conversation depending on the "status" of the person with whom you're speaking, through making sure you don't leave your hashi in the bowl and which sauce goes with which food, through everything else in general behaviour.