Pale skin is an epitome in Asian culture. In other words, many Asians view pale skin as a standard of beauty, but it's just for the girls though. If a guy is darker, then they won't view that as a negative thing. Guys are usually darker than girls, so it really doesn't matter if a guy has olive or tan skin.
Edit: I agree with Shellster. To Asians, if a girl is lighter, she is viewed as prettier. This is also the reason why Japanese geisha's paint their face White, like this: