This is relevant to me, because my heritage is eclectic. It's easy to overlook at first glance, but if you know what to watch for the clues are there -- like how white girls don't have hair that breaks "unbreakable" combs. Actually, the best description of my ethnicity is one bestowed by a black friend in college: "Yeah, you can pass for white -- until you open your mouth." Because I still have an affinity for various cultures and will stick up for them whether I currently look that way or not. Conversely I do not feel compelled to support evil people just because we bear a superficial resemblance. This in particular got me in trouble throughout much of school. I'm not against white people; I'm just as fond of my Celtic ancestors as my Cherokee or African ones. But neither do I feel much affinity for modern American culture, and I don't think any culture is special just because I'm standing in it. This sets me very much aside from others.
It means always being an observer, seeing things from multiple perspectives instead of just one. It makes life more complicated. But it also makes things more interesting, and I wouldn't give that up.