I remember one of my tutor's in college, he kind of was tan so I thought he might have been Persian or something..When I asked him, he seemed kind of offended, he was like "What, I don't look White to you?!"
but I've noticed that with people of mixed descent tend to overemphasize their "white side." They'll say "I'm half <"other race">, a quarter German, 1/5th Dutch, etc.." right down to the exact percent instead of just saying half-white. hmm, I wonder why...