Mountain Biker at heart, Roadie as a means to an ends.
I love riding and racing (occasionally) my mtn bike. I use my road bike to train.
I ride my mtn bike when I want to go solo (even in a group situation) I feel you're more secluded in the woods on a bike, good time to hammer and just think. I feel more in tune with everything around me when I'm on my mtn bike.
When I ride my road bike, it's usually with a group of 4 or 5 and we're constantly talking, pulling through and just more social. I do ride solo on the road, but it's usually only for about an hour and it's over before I really get in my "solo" groove. When I'm on the road, I'm usually concentrating on not getting hit by a car! That, or keeping track of my speed/cadence/heartrate.
I just feel more free on my mtn bike.
L8R
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"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming, "WOW, What a Ride!" - unknown
"Your Bike Sucks" - Sky Yaeger