8. Lots Of Humans - Battlestar Galactica
Battlestar Galactica's finale remains one of the most divisive and controversial in TV history, from the fates of the major characters to the way so much of it came down to being an act of God.
While we see some of the crew die in the finale, though, for the most part it's supposed to be a relatively happy ending. They make it not to Earth exactly, but to a close-enough version of it that it gets the same name, and we end up seeing over 100,000 years pass, with versions of Six and Baltar still existing. But the rub comes from the original colonisation of this new planet.
In doing so, the survivors who've been aboard Galactica decide to discard all technology. They're beginning with a clean slate, which is nice in theory, but that also means depriving themselves of so many things they've come to depend on. Without it, many of these survivors would have a greatly reduced quality of life and a shorter life expectancy, leading to many of them dying in various ways, including death, famine and so on.