I have no respect for characters who habitually don't wear shoes and/or socks.
Let me just say that this does not apply to real people, although this does bother me in live-action as well as animation. And, even though it shouldn't have to be said, this doesn't apply to non-humanoid characters, characters who are incapable of wearing shoes or foot coverings of some kind, or those who have no access to shoes for whatever reasons. Last, this doesn't mean I don't like those characters that run around barefoot everywhere, but they usually don't get on my favorites lists either.
What I don't understand is why people flock to this design flaw. It doesn't make a character look more seemingly innocent for not knowing that he or she could get lockjaw from stepping on a nail. It doesn't make or her him look more tough in that their body has been hardened to the point where he or she needs no weapon. It just makes the character invariably look like a hygene-impaired idiot and alienates me as a viewer. Don't wear shoes if you want, but if there's a cold snap and it gets 30 below, don't come to me with your frostbitten, dirty, bare feet. You deserve any anthrax or SARS you get by stepping in your opponent's blood.
Put on some shoes, please.