Watching the Space viewer's choice remastered marathon on Space and I couldn't help but notice all the times Spock is referred to as Mr. Spock by other members of the crew who are junior in rank to him. They barely call him sir, or Commander. Was this an intentional writers decision by the writing staff? Or just an ongoing mistake? I understand the original Enterprise has something of a "loose" command structure but it bugs me when someone calls Spock Mr. Spock. Even in The Undiscovered Country he's referred to as Mr. Spock instead of Captain or sir.