Giving up ones work is for those who have no dependants but, I got some roller blades a couple of years ago and enjoy ice skating and other sliding sports. This gentleman's angular acceleration theory is good, but I think that there is more to it. We become aware of the living vehicle in which we ride by sliding. Marc Bolan knew car-girl, and "When I am sad, I slide"
I will try my roller blades again as soon as the weather clears.