Matters of the heart - Attraction

Part of me is unhappy with having heart in the title of this post; perhaps it should be hormones, or, conversely, mind. I've been thinking more and more lately about what it is that draws me to certain people, what are the attractive qualities that most appeal to me, what part of me it is that's attracted to them. Why can some people have eyes only for one person, no matter how that person feels or how they treat them? How is it that others are always attracted to multiple people and struggle to commit to one attraction.
Personally I have identified different kinds of attraction in my own experience. There's one boy who I literally just want, not exactly in a sexual way but just in a he will be mine kind of way; perhaps the unattainability of him is what makes it so difficult not to have a pang of yearning when I see him. Another kind of attraction is that residual feeling you always have for someone you've had something with before, its comfortable, you know what to expect and you know what you like about them and how to avoid what you dislike about them. When it's someone you've loved you can't help but be drawn to everything you know to be good about them. There are some who are purely physically attractive, mr sexy in the club when you're high on life and just need to press up against somebody;the thrill of the unknown, the thrill of knowing they want you just because they think you're miss sexy, its flattering and exciting. Finally there's the person you like because you connect mentally, someone who sees you for who you are and how you think, who really listens to your opinions and who's opinions you find yourself caring about. That person who isn't obligated to take an interest in your mind or your feelings, who you don't expect to compliment you, who you don't expect to suddenly find yourself attracted to.
I guess this is why you can sometimes love someone and still be attracted to a stranger, to still want to have a conversation with that old friend and still think fondly of your ex. Having been in love though, one discovers that attraction pales away in comparison to that connection; it doesn't stop attraction being compelling but it sure helps not to have to depend on attraction and analyse where it's going.