I guess it's obvious, it's a luxuary problem we have, I had one myself as well just for the nice looks of it, but didn't like it after a while so went back to a normal bike. I still have a normal bike as I didn't start on my driver's license yet....stupid me, because the governement keeps making it expensiver every year and more difficult to pass for it.
My brother has a mountainbike, but a kind of racing version. He uses it for sporting and used it a lot untill he went to the marines. So now he only uses it sometimes in the weekends.