Humans know when it's not a good story. Unless you do this for a living, you may not know exactly why you don't like a story, but you can't fool an audience ever. They know when you have it and they know when you don't.
I try to turn a written thing, when I'm in trouble with it, into a spoken thing: I start imagining what I would say to someone if I were trying to tell the story or make the argument.
Curious things, habits. People themselves never knew they had them. [Witness for the Prosecution, also published in The Hound of Death and Other Stories.]