If you live somewhere where it's warm year-round, be careful with going completely barefoot. The issue is a parasite called hookworm that enters through the skin.

If you've ever seen photos of, say, young boys going fishing in the American South, you might have noticed that, in spite of being dressed for warm weather, they have shoes or boots on. Now you know why.

That said, I spend most of my time indoors either barefoot or sockfoot (to use a term I first heard from a Japanese friend). Outdoors, I'm either in Crocs (just too easy to be able to step in/out), negative-heel trail-runners, minimalist sandals, or barefoot - but I live in New England. As a college student, I tried barefoot in the winter snow for about a week (was trying to figure out how the native Americans managed it). I don't recommend it.