My reaction to questions like that is always, "Why would I sort my friends by race (or whatever)?!"

"Do you have any friends whose phone numbers end in 7? Who have 'e' as the second letter of their middle name? This is not why I'm friends with them!"

Do you suppose that your instinctive answer of "no" is because your default is to treat black people differently from non-black people (thereby making it less ridiculous to assume that one could intuitively sort one's friends that way)?