Not our physical differences, but the importance we place on how we look, and how the opposite sex looks. For guys, looks might initially attract you to a girl, but then you want to get to know the person and see if she has a good personality. Girls do just as much checking out cute guys as guys do checking out cute girls. But if they're not a good person, they become so much less attractive. People are more attractive if they have a better personality.
Girls often feel pressure to look good all the time.
That's like every message we girls get. As a Christian, I know it shouldn't make any difference how I look, because beauty is fleeting. It's what's on the inside that counts. But it seems like girls just have to impress people with their looks more. But when I go out, I try to look good, because I know people will look at me and kind of scrutinize me.