I posted a version of this elsewhere long ago, but the topic warrants more attention. I am the Public, and this is my Outcry.
1) Do not leave the story open-ended. I didn’t sign up to read this book or watch this show so that I can figure out my own ending. It is not a “choose your own adventure” book. Issues must be resolved, and if you leave something out, unfinished, I will notice. Now, if the heroine walks out into the ocean to kill herself & you stop there (The Awakening?), that’s fine; I can piece that together. But if sharks start circling just as she spots a sailboat with her lover on it…not cool. Some writers think this is an artistic option to ending a story, but I usually feel cheated. I have too much imagination for open-ended endings–I come up with too many ideas and then can’t choose. I want to know What Really Happens. I find that far too many YA novels leave off an ending in the hopes that a cliffhanger will make eager readers line up outside of bookstores the night before the sequel’s release. I will not be in those lines, and I will definitely not purchase another book in the series.
2) Never kill the dog. Examples: Where the Red Fern Grows, Old Yeller, Benji, and I Am Legend. All stories or movies that I never want to think about again. I watched a really terrible Sylvester Stallone movie from the mid-nineties (no, I don’t know why I watched this). All these people die in this tunnel disaster, and it looks for awhile as if the dog dies too. Then the dog shows up, alive! So even though the acting and plot left much to be desired, the dog lived and I would re-watch this movie any day over seeing I Am Legend again. If there’s a dog, and it lives, sign me up. If the dog dies, I want my money back. Now. And a memory erase procedure, a la Eternal Sunshine Etc., so I don’t have to think about it. This rule also applies to cats, but thankfully I can only think of one piece of literature to support it–some Poe story about midway through a collection I own. I stopped reading through the collection at that point. (Although I must point out on a tangent that “The Cask of Amontillado” is one of my favorite stories.)