I agree about biases. As intelligent people, we can say "it's stupid to have preconceived ideas about people because of their race", but in practice, it's hard to follow.

I grew up in a mostly white town, and didn't really know many black people growing up - so, I don't really know a lot about black culture. Thus, I tend to sometimes get nervous around black people, because I don't want to offend them without thinking.

It's a real problem.