When I was a child, we'd officially shed our shoes on the last day of school. After that, almost the entire summer was spent barefooted.
It would take a few weeks, but our feet would develop calluses similar to leather. At around 1/4 inch thick, they would protect our feet from anything, except broken glass bottles. We could walk across hot asphalt paving without flinching. The oyster shell parking lots, which were common at that time, required walking carefully, but didn't stop us in our travels.
Our feet took a beating. The worst was usually a missed pedal, which dragged the top of our foot under the pedal of a bicycle. This usually took off a substantial piece of hide, or most of a toenail. This would slow us down, but we still avoided shoes. Blackberry vines were a concern; they wouldn't hurt the bottom of our feet, but the sides would be scratched if you weren't careful.
I remember riding on the handlebars of a friend's bicycle. This required sitting carefully and placing my feet on the two bolts that held the front wheel in place. We were in hurry, so he was peddling as fast as he could. When he hit a bump, I lost my footing, which pushed my foot into the spokes. The next thing I knew, I was face planted on the paving and wondering what was broken when the bicycle, and friend, suddenly ended all forward motion and fipped onto my back.
After a few moments of analysis, I realized I had some scrapes, my foot was bruised, but not broken, and I would survive. I shook it off and we went about our business, although I did limp for a few days and we had to replace some spokes on the bicycle.
Today, my feet are no tougher than those of a newborn. There are no calluses and the smallest of twigs makes me flinch. It would be impossible to walk on hot paving and if walking across a shell parking lot was the only way I could get food, I'd probably starve.
There is a saying "No man is an island" ...I'll add, "unless he doesn't have shoes".