From apparently harmless intergalactic surveyors to seemingly friendly space hitchhikers, Star Trek is littered with too many examples to count of one-off guest stars who end up double-crossing the crew. When the premise of an episode focuses on a mystery of any kind, too often are we forced to wait around for the crew to slowly discover that the benign fellow who sent a distress signal in the cold open is shockingly to blame. Just how many times has it turned out the guy (or gal) we’ve never seen before prior to this episode has a secret, hidden agenda? The shifty eyed dog from The Simpsons was less of an obvious villain than some of the fellows the Enterprise has encountered. It shouldn’t take the combined intellectual efforts of Spock and Constable Odo to figure out the correlation between people turning up out of nowhere and sudden spikes in the rates of violent incidents/sabotages/kidnappings/thefts/mind rapes, but the crew always seems legitimately surprised by the duplicity of the alien they just met.
But how often are they running into strangers that don't cause enough drama to warrant an episode? They must run into that situation enough to prevent paranoia?
I've seen that referenced as a common trope on TvTropes. I can't recall what the trope is "called", but the format is always the same: at its simplest there's a list of three, with the third example only existing in that universe.
Nazis episode. Episode that kicks over the social justice hornet nest due to being a Technologically And Therefore Morally Advanced Culture's Burden plot, most likely by accident. Episode that pulls off a timely, relevant issue with the grace of a ballerina that sadly becomes dated by the final season. Episode that pulls off a timely, relevant issue with the grace of an elephant trying to build a ship in a bottle. Space battle episode by someone who has no understanding of three-dimensional combat. Space battle episode by someone who has no understanding of anything except three-dimensional combat. Back To The Present episode. Mind Controllers/Manchurian Candidate episode. Trapped Behind Enemy Lines episode, bonus points for the captain/first mate and whatever love interest the writers will push on us being the ones trapped behind enemy lines. Episode where they Go Really Fast or test some other feature of the ship, but something goes Horribly Wrong. Since anime has catapulted to the mainstream (thanks largely to Netflix IMHO), Plot Directly Stolen From Anime episode. Your pick of Space Battleship Yamato, Robotech/Macross/Gundam, Gunbuster, etc. (This only applies to DIS) One-off character with the personality and charm of a used car salesman who inevitably stabs the crew in the back. Retiring cast members by killing their character. Some disease, whether viral, bacterial, parasitic or genetic, that causes All Kinds of Weird Things that no disease should be capable of doing to one species, let alone hundreds.
And we can't forget two characters who can't stand each other being trapped or held prisoner together and have to depend on each other to get out of the situation. Quark/Odo and Tuvok/Neelix come to mind. Oh, and Dukat/Kira and Dukat/Sisko.
Our Heroes will be in a small group with outsiders and feel compelled to have a discussion about one or all of them. Even though they could easily leave the immediate area, or room, to truly discuss the matter in private, they elect to say something like, "... if I may have a word with you, please," then they'll step a few paces to the side and audibly discuss whatever they don't want the others to overhear. Then, they'll retrace those few steps back towards them and inform them of their decision, or act on whatever it was they discussed ... and Our Heroes never get told things like, "... I can hear you AND your bullshit plan, by the way!" It's always like those being discussed decide to not pay attention and zoned out to respect the "privacy" of the conversation, or something ...
The transporter suffers a staff malfunction- Tuvok/Nelix (Tuvix) Picard/Guinan/Ro/Keiko O'Brien (12 year olds) Riker's duplicate, two Kirk's etc. Never trust the transporter Chief on duty hahahaha
Wrinkled foreheads, guest stars challenging the natural order or teamwork of the main cast, and random ensign calling out shield percentages.
The universal translator doesn't translate when people deliberately want to speak in an alien language Other starship crews exposed to deadly diseases died because they were more stupid than our heroes.
Eh, characters talking about private matters way louder than they should be is more a general TV thing. See the CW superhero shows, in which characters commonly have very audible conversations that should compromise their secret identities in crowded public places. The rule seems to be that if the extras can't speak, they can't hear either.
Characters getting abducted/brainwashed/replaced by evil alien duplicates while on their way to or from a conference. Attending a conference is one of the most dangerous activities in the entire Federation.
Maybe it’s a little too much to ask for every single device to be in constant working order, given the host of other problems that engineers have to deal with by the second - but the inability to use transporters because of “interference” or some other cockamamy contrived reason consistently puts away teams at risk, and racing the clock. Of course, whether there’s an alien predator, the business end of a phaser or an extraterrestrial earthquake threatening the team, the problem is sure to be solved by the miraculous revival of the transporter with literally not a moment to spare. How refreshing, just once, would it be for an away team to be transported back to safety with a good 15 minutes remaining until an explosion? It would be much safer, not to mention a lot less stressful for all involved. "What’s that, helmsman? It’ll take about 3 seconds for us to warp out of the blast radius? Make it so!"