I actually prefer to walk barefeeted as often as I can. Feels more comfortable, unless the path is covered with small rocks or not so thick gravel.
But gravel is very healthy to walk on. Sure it takes time to get used to it, but it cured my flat feet.
Just avoid cig butts, broken glass, narkoman syringes, sea hedgehogs, sharp stones, hot asphalt, dog crap, bubblegums, bureks, kebabs...