The comic urban fantasy started out fun. The heroine had been a demon slayer in her teenage and early adult life, then she’d put aside her slaying tools and become a wife, then a mother of two small kids. She’d never told her husband about her Buffy the Demon Slayer days.
Then a demon shows up at her home and tries to kill her. She dispatches him. Another, more powerful demon threatens her children’s lives, and he’s also in her home.
At this point, she decides not to tell her husband about the demons after their kids or about her past because it would be awkward.
This is the moment when I stopped reading. The author had failed my reality sniff test.
Sure, this is a comic urban fantasy, and readers know that the kids will be okay, and the heroine will win against the demons, but the heroine has done something that, in the real world, most of us would find selfish, stupid, and unforgivable. She is risking the lives of her young children.
Books aren’t bubbles that have nothing to do with the real world. Yes, we will accept wild premises like ghosts, vampires, and demons, but most of us enter a book’s world with our own beliefs and views of the world, and the author who errs in those common beliefs because she thinks that we will put them aside in her book is often wrong and loses a reader.
When you are writing, consider the reality sniff test. Do your characters act the way someone in the real world would? Is that behavior acceptable in the real world? Does your worldbuilding make sense in comparison to the way the real world is? Does your world/society fit a society from our past, or can it be imagined as real? If the answer is no to these questions or other reality sniff tests, then you need to do some rewriting.