Occasional thought...Why do ghosts wear clothes?

Seriously....the people whom witness some ghosts claim they are dressed in "time" fashion? Their hair is a certain way? So your telling me that if I dress like a clown for my sons birthday party and I happen to die, I'm forever "imprinted" as a ghost clown? Say I get a bad haircut, I die, so I'm assuming that I'm stuck? From what I believe hair is dead, clothes are not made to span the ethereal plane....any suggestions?