I, we, and you
If we try to fit in a multi-cultural society, who we have to know about is not only people from different backgrounds.
There are something I needed to be aware about people from my home country(!). If a Japanese born in US is called Japanese American, Japanese from Japan living in US could be called "Just-a-little-bit-American Japanese". And to what extend s/he is american depends on individuals. So what I need to see is "To what extent is s/he US person?". For example, let's see I sent an e-mail to somebody and I made a phone call to make sure if the e-mail was actually sent. A Japanese would say thank you for the phone call in this case. But (I feel) I should not make this kind of phone call to people from US, because it sounds like I am proding him/her to do something.
Sometime, it's hard to assume what people in the same origin are like. The grayzone of "Who are you?" is sometime tricky to handle.