Responses
a bad story includes bad writing and plot, if the story has a bad ending but it's well written then it's a tragedy story, example of this are Code Geass, Death Note, Wonder Egg Priority, Platinum End and Kuma Miko, or/and Attack on Titan. As u can see they're all well written but the ending is bad where the main character fails, so is it considered a bad story?
I think people shouldn't consider stories with heavy themes and bad endings a bad story..