It's not necessarily my favorite episode but it pops up always when I think of ST
It's voyagers episode where they observe the planet which is in its own time pocket, so the whole evolution of the society happens in days from voys perspective
The first time I saw it, I came in a couple of minutes late, so I missed everything changing into an alternate timeline. I saw Tasha and thought, "is this a repeat?" And I thought, "no, the uniform is wrong." I still think it would work better that way. Start it with the Enterprise C coming through the rift and the timeline already changed.