2. The Doctor. Very interesting how he's essentially just software like Data was, but lacking corporeal form he gets treated like junk by the crew rather than respected as Data was. The only difference being the Doctor's lack of corporeal presence.
Actually, this bit would have been one of the best bits of 'hard' scifi in media if they'd managed to pull off what I think they were trying for correctly.
To steal a term from Mass Effect - the Doctor was orginally intended to be a 'Virtual Intelligence', not an 'artificial intelligence'. Consider how Data ended up going through a trial to try to determine whether he was an AI or 'just a machine'. How realistic the holographic 'actors' were on the holodeck, Moriarty and such.
Roughly speaking, a 'Virtual Intelligence' is still just a machine, a computer program. But it's one that has been programed enough and is actually capable of some level of 'learning', but isn't actually sapiant or aware. Within it's role, it's capable of imitating intelligence very well, though outside of flawed presentations I figure that the 'real' people of Star Trek can quickly spot VIs from actual people or even AIs. You see some of this in some of the better holodeck episodes where the crew, still in uniform and some alien, enter the holodeck and representations of ancient people act like they're perfectly normal.
So the idea was that 'The Doctor' starts out as a VI, one with a particularly abrasive personality at that. Very much not a people person, because in universe most of the development was by a man who in real life would probably test as autistic - all the care for the biological functions, but a horrible interface for most people. Basically a holodeck character with realworld medical procedures wired in. A form of autodoc, if you will.
But they mostly screwed it up.
Starfleet (fictional) it's customary for all officers to be addressed as sir. Regardless of gender.
Go to the subsection labeled "Sir" about 80% of the way down.
Interesting... I've heard about some militaries in real life doing this, but I wonder where in the backstory they implimented this tradition, or have they even bothered? Could it have popped up when they started dealing with aliens that were of non-standard genders(can think of like six variations off the top of my head), or some lingering symptom of 'equal opportunity' gone mad?