Are you absolutely, completely and totally sure that's correct? (lol?) I don't agree with this, because many dark endings are quite pleasurable. You personally have hope in the future and the ending to that last piece of fiction helped with your resolve. Orwell's majors did that for me, 1984 and Animal Farm. At least I can't help but think those are not prophecies of the future.
I like endings that are sort of neutral, or open to interpretation. Those are the endings that impact me the most, because you don't know if something bad or something good happened. The movie Inception is a good example, as it is uncertain if the Spinning Top at the end fell or kept going; I think it fell but a lot of people think it keeps going.
