DL, You know, I think that the majority of my sex drive, which is physical-based is due to the fact that I have identified myself as someone who likes sex, in the same way that I have identified myself as someone who loves water and music. Since I have already established that I like it, I tend to think about it and look forward to it. This is half the battle, imo. Thinking about sex--in great detail--how could it NOT arouse a person right! I do agree that I have a certain hormonal cocktail going on that facilitates such an attitude but I don't think it can be boiled down to strictly hormones.
And, like you said, a lot of is just personality..whether you are easy going or anxious. My anxious H has a hard time relaxing and mentally getting to the point where it sounds good, whereas extraneous chaos affects me much less. This is both good and bad. Good in the sense that my R doesn't suffer because there are dirty dishes but bad in the sense that I need H's structure to keep me in the service-doing mode so that my house does not become a pigsty. I have agreed (though this was never an 'outloud conversation' that we had) to keep the house as neat as I can in order to alleviate the inevitable stress that he feels if the place looks cluttered. Although this wears me out somedays, I consider it a fair trade. And understand that I am not literally talking about a "trade" that is just the best word I could think of while typing out a post and opening some string cheese. I think of it as something that gets him in the right frame of mind, much like I dim the lights and talk softly when it's bedtime so that my kids make the mental jump from being wild dogs all day to calm little girls ready to head off to bed.