Originally Posted by
Knaight
It's worth considering surfaces here. The vast majority of relevant human evolution took place in central Africa*, where the ground was generally comparatively warm and soft. On the temperature side, there are surfaces that can get way too hot for barefoot walking (asphalt comes to mind, but sand can get pretty bad too in places and that's been a problem for much longer), along with fun stuff like snow. On the hardness side, asphalt and concrete are ubiquitous today. Neither are what we evolved to walk on.