Lol my brother and dad keep going on about cars and i dont know why! haha whats so special bou them... Hmmm ... Me?, i prefer shopping wiv ma girlee's XD
Speaking as one also not into cars, I think a large portion of it comes from being able to tinker with the machinery, and especially in people who start out with kit cars, actually putting them together, improving them, tweaking them, and essentially making the whole thing yourself. Personally, I'll stick to coding, it's easier and cleaner to put together. But that's the way I see it, anyway.
Personally I love working on cars. Mostly because I can use my brains+muscles to make my car better. An added bonus is a friend's envy.