Something about shirt colors that has always bothered me. I get that Blue is for Sciences and Red for Operations, but why is there need for Gold to be worn by anyone but the Captain and what distinguishes those who wear the Gold shirt but who are not the Captain from those who do not wear Gold. I have always thought that Gold was for Command Crew. Ok, so then why aren't Spock, McCoy or Scotty (all holding command positions) not in Gold? If by Command Crew, we mean Bridge personnel only, then why isn't Uhura also wearing Gold? Sulu is OPs, so he could have been in Red. Chekov is Spock's protege and is portrayed as being something of a prodigy, so why couldn't he be in Blue? Do you start off as a Red or Blue shirt and then get promoted to a Gold shirt (but then that doesn't work for Spock nor Scotty)? It seems to me that if you are in the crew, you are either involved in Science or OPs, or a combination of both, so why have Gold Shirts at all for anyone but the Captain? I realize that the practical answer is that GR and Company probably wanted diverse colors on the set for aesthetic reasons, but I am looking for a more in-universe type of explanation please.