Depends. For some, it's an outward projection of their hopes and dreams. For some it's protection against the elements. In my case, it's to wick up sweat and let it evaporate to keep my body at a comfortable temperature, or to insulate against environmental conditions that I don't care for. I wouldn't be adverse to nudity if that was the custom. I sometimes like to look "fancy" (every man needs a nice suit jacket - I'm a believer in that), but usually I like cotton comfort. But in the end, I like comfort. Other people wear clothes because they don't look like the people they imagine themselves to be. And.. they fear ridicule. #1 reason.