I agree, life is already full of pain and misery, so why have it in fiction as well? but at the same time, I don't mind a bit of tragedy, angst, etc as long as there is a happy ending. I think that there needs to be a bit of pain, angst, etc for the plot to be more real and more believable but the ending should always be a happy one because there aren't enough happy endings in his world.
I actually enjoyed Ai no Kusabi, even the ending (which totally had me crying). But I enjoyed it even more when I went online and read fanfics where they had a happy ending instead
