When I got my first proper MTB back in the early 90's, my riding partner had an Aluminium O. If a roadie ever passed us he used to take it as a personal affront and chase and overtake them, just to make a point!
I tried it for a while when I had my P7, with occasional success, but that was about 15 years ago and I daren't even try now. Having said that, I did take the road bike out for a quick spin last night and had forgotten just how quick (and uncomfortable!) it is by comparison to my favourite toys.