do you wear shoes?

Quite often I will take off my shoes at work. I don't walk around without shoes, but if I am sitting at my desk I often remove my shoes. It is simply more comfortable that way. I just walked out of my office and I spotted a pair of socked-feet sticking out from another desk. And the other day I went to talk to a co-worker and he had no shoes on.

Do we all do this? Why do we wear shoes in the first place?