I'll be honest with you. This is one thing that has always annoyed me about Star Trek, in all it's incarnations. Why in gods name would everyone wear the same clothing? There isn't a nation on earth that has the entire population wearing the same outfit. Yet we see this time and time again on Star Trek (and Farscape too, i'm noticing). I guess it has to do with speed of designing and creating costumes for all of the cast on each episode, but really. This little tidbit drives me insane.