Remember going barefoot as a kid? Probably summer. The sometimes smooth, sometimes slightly rough texture of sidewalk cement. Cool green grass. Dusty slightly slippery dirt. The rough surface of a tree branch and the hot sand between your beach towel and the water line. Blazing hot black asphalt when crossing the street. You could go "ouch, ouch, ouch" and resort to dancing along the white pedestrian crossing paint, or endure the burn, suppress the urge to hurry, and feel immeasurably cooler than the person next to you going "ouch, ouch, ouch". The pleasure of sensual extremes, all relayed to you by your feet.
Long for the days? Ever tried it as an adult? It's not the same. I go barefoot around the house and in the yard every day of the year. Even with that though, straying out onto the asphalt is not a comfortable thing to do. The soles of my feet are not as tough now as when I was a kid. I don't go barefoot in all conditions as I did back then, but I think there is more to it than that. I think physics has gotten involved. Something about doubling the surface area and the resulting volume quadruples. There is more pressure per square inch on the feet of an adult than there is on the feet of a child.
But I wonder if that physical difference is insurmountable. Could an adult get as comfortable walking without shoes on all surfaces as a kid can? I don't have a theory, but maybe I should test it anyway. While I'm barefoot already, I could make it a point to venture out onto the rough asphalt every day and see if it gets any easier after a few weeks…