What are your top five Star Trek episode concepts?

I don't care if the episode itself was any good, bit which episodes had the best premise?

@ajroach42 the concept of Voyager itself was good; a Starfleet ship in the middle of nowhere, cut off from Starfleet and the Federation, and struggling with the idea of adhering to Federation ideals, while also consisting of a crew made up of Starfleet and former-Starfleet-turned-Maquis members, who have a different stance towards those Federation ideals.
Unfortunately Voyager never really did much with that... the Maquis fell in line way to quickly […]
@ajroach42
[…] and judging by the amount of shuttles they lost, torpedoes they used, and how the ship almost always was fully repaired in between episodes, the supposed lack of resources never truly seemed to be an issue, save for for instance the Year of Hell (which iirc featured a big reset button afterwards anyway, and thus was a good wasted concept as well). […]
[2/3]
@ajroach42
[…] I think I've written it before here on Mastodon, but I probably would've enjoyed watching the journey of the #USSEquinox from #STVoyager more. Watching how they slowly but surely lost their struggle to follow the #Starfleet/Federation ideals, even though it would've been at odds with #GeneRoddenberry's utopian view. [3/3]