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.