@chrismessina Just learned about the science behind this in a genetics class..
Turns out people's immune systems and the genes within them vary greatly. The more variation there is between your system & another person's, the more you will find them attractive (for evolutionary/survival reasons). The way we can sense this is through SMELL! If you find that someone smells good, it's indicative of them having an immune system that's varies from yours. They're a good 'fit' for you :)
This concept exists in reality. Interesting to see it in mail "odor" form. Check out the pheromone parties that go on all over the world http://www.pheromoneparties.com/
How it works