If you see someone who you're attracted to, then instantly you make a subconscious judgement. If you're out, you look at someone, and if you're attracted to them physically you will talk to them, no one's ever looked at someone, thought they were hideous and said to them self "That's who I want!"
It's the looks that attracts someone, it's the personality that keeps them. Everyone shallow about certain things, e.g a lot of men won't date fat girls. Which in its self isn't bad, because they chose to be fat, they chose to not lose weight, so they can't complain that guys don't want to date someone who often looks unattractive because of their weight, and have health risks.