Of course this is written by somebody who sits a lot. As to other simple pleasures I recall Henry Miller (or if it was Arthur Miller) saying in a TV program that urinating was one of the great pleasures of life. I, a romantic, poetry reading teenager was shocked! Later I realized that yes, it could be that.
Back to walking. After a number of hours of sitting, reading and writing I hitch a hike with a friend to the nearest town. When I step out of the car it strikes me: Wow, what a pleasure it is to move my legs, to walk, stroll and promenade. The feel of trouser against leg, cloth against skin, what a sensual, simple joy — one of the many free pleasures in life.