Maybe a small ranking, from most-best to least-best:
3: The TOS films have a certain aesthetic that feels the most plausible - nothing garishly cluttered or littered, feels utilitarian. No replicators meant they had to keep food and other supplies on board. They never really did go into detail on the "food synthesizers", though STVI revealed a proper kitchen... and Kirk tells Charlie X that he has to sculpt synthetic meat loaf in the shape of turkeys and that simply isn't done on Scotty's hot engine, or - even less appropriately - Spock's console. The uniforms (save for TMP) look just like that - uniforms. No RGB spectacles, but subdivision hues separate to the main uniform do adorn where applicable. TMP's look like a special themed pajama party event at Studio 54. But every rule has its exception (even that one! Tell that to AI and see how it handles the resultant equivalent of a "divide by zero" or "false generalization" error with the adjective-overload verbiage, and requiring much more time to process and reply than any human could. But I digress (
naaah, really?! 
) )
Also,
@Cmetz94 nailed it - the universe wasn't such a small place back then. In a different way, it wasn't as insanely big a one either.
4. The gripes of "space hotel" notwithstanding, there does feel like an evolutionary refinement - one that doesn't go over the top with the bulk of its concepts, though what the holodeck can or can't do every other week is borderline -- while we suspend disbelief for transporters, and replicators are now a claimed technology*, the inconsistency of holodeck use is grating, especially when its terms were largely defined in early-season 1. Of course, they didn't have script writing software and greater forms of networking back then so discontinuity and forgetting about the "Star Trek Bible" or whatever they called it is more likely to happen. There was also once a technical manual that once implied how any ship function function could be routed to any display's touch interface, even if that was rarely shown on screen. Which I agree with since:
(a) not only do our phones change interfaces between applications and home screen and they all share the same of tactile-nonresponsive glass**, it's not a big issue to generate a control panel from a centralized mainframe and push it out to any display node
(b) we've seen
x-number of technological advances come about because some sci-fi script writer scribbled onto paper an idea recited by an actor who had to take what seemed to be asinine and play it with sincerity, so that the audience could buy into the "magic" as well.
Lastly, Q had to tell Picard how there were real terrors in the universe that made Klingons and Romulans seem like nothing by comparison. Which is sad, given all the weirdness that has already occurred in TNG by this point, especially in season 2 that reaffirmed this very core concept, and given how often characters in season 1 belched out comments about "the old Enterprise", it's amazing Data didn't say every week how comparatively dangerous it was when Charlie X was around or when the big space amoeba threatened to do what the giant space windsock was doing via another method a few weeks' earlier. At the same time, it's Q giving Picard another push, as finally confirmed in "All Good Things..." on how Q has been trying to help the guy in learning new perspectives all along and hoping Picard would get his head out of-- so anyway, anyone have a recipe for a stout chocolate milkshake? TNG season 2 is dreadfully underrated... TOS and early-TNG definitely had the biggest dangers to face and overcome, and didn't excess in proverbial navel-gazing until later on.
* Yay, it's footnote time! Current media hype and salivation over "3D printers" stretches credibility even worse than the TV show, since their script writers never watched the show. A show that at least kept consistent for the most part on one aspect: The replicators used energy and turned it into matter. It did not take matter and reconstitute it. The replicators shared the transporter's database, where
patterns of said foodstuffs were saved. The 3d printers merely transform matter into another form using a directed thermal reaction (heat, to soften the thermoplastic filament*** with.)
** do your fingers and/or tootsies feel more sore after eight hours of typing on spring-loaded keys on on a big piece of glass with some piezo buzzer underneath vibrating for every tap?
*** this is derived from corn husks and is recyclable. Just don't tell that to anyone who's eaten dish detergent pods. Technically it is edible, unless the dyes used to create those lovely hues has incompatible if not outright toxic elements to one's biological body. But it's far, far cheaper to run out and buy a bag of corn husk leaves. They aren't any tastier. But, if nothing else, any critter that eats corn husk leaves can be fed that little plastic figurine once you're done with it. But if you really want tons of raccoons and deer roaming around every night at the same time, go right ahead with that award-losing idea.
