When I've talked with other white people about racism in America, they've often said they think it's largely a thing of the past. What they (like myself, until fairly recently) often don't understand is that being black or brown in a predominantly white community changes the way others react to you in usually subtle, but constant ways, and you feel differently about yourself as a result. I'm sure the same thing happens if you're white and you live in a community that is predominantly of color: you stand out, and other people make you feel it. (And your attitude toward your own difference also contributes.) In any case, constant awareness of one's difference from the surrounding community has an up side. Here's V.S. Naipaul -- born in Trinidad, whose grandfather came from India -- on the topic, describing what it was like for him to go to India for the first time and lose his sense of difference:
And or the first time in my life, I was one of the crowd. There was nothing in my appearance or dress to distinguish me from the crowd eternally hurrying into Churchgate Station. In Trinidad to be an Indian was to be distinctive. To be anything there was distinctive; difference was each man's attribute. To be an Indian in England was distinctive; in Egypt it was more so. Now in Bombay I entered a shop or a restaurant and awaited a special quality of response. And there was nothing. It was like being denied part of my reality. Again and again I was caught. I was faceless. I might sink without a trace into that Indian crowd. I had been made by Trinidad and England; recognition of my difference was necessary to me. I felt the need to impose myself, and didn't know how.
--From p. 39 of V. S. Naipaul's
An Area of Darkness: A Discovery of India.