I'll try to explain why I love dancing — actually, I'd never thought of it as a passion before. There's 3 aspects, as far as I can see.
(1) There's the visual beauty: Your partner makes beautiful steps, and you can just watch and think how beautifully she moves. Admittedly, most dances are more about ladies making pretty moves while the lad just does the basic steps, but I'm not complaining
Also, there's the knowing that what you're dancing looks beautiful to others: I know many people like to dance near a mirror.
(2)There's the beauty in the movements. I'm not talking about how they look, I'm talking about how they feel. There aren't many other situations where you can try to make the sexiest hip movement possible and top it off with a flick of the hand, without feeling inhibited. Dancing is one of the few 'sports' where the movement is an end unto itself, where you don't have to wait for a desired effect. There's also another feelgood factor to do with movement: your partner moving in you arms is a wonderful feeling
(3) There's the fixed set of rules. Improvisation can be very scary, but in dancing your choice of movements is limited but still very large. It gives you the security of a framework, which makes you feel safe.
So for me, dancing is about making beautiful movements, feeling and seeing their beauty, and knowing that I can't possibly be blundering, whatever I do next. But the first 2 points are by far the most important to me, because I never cease to enjoy beauty. The added value of dancing, is that I'm *participating* in the creation of beauty, not merely watching. Same reason people sing along or play an instrument, instead of just listening to music.
I made this post long because I lack the time to make it short, to paraphrase Pascal. Sorry.... I hope this helps, a bit.