Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Tough Luck
The entire tone of The Rules of Survival is a little bit of darkness and a whole lot of no-nonsense honesty. After all, it's told from the perspective of Matthew Walsh, who has lived through some difficult family times with his abusive mother, Nikki. He can't exactly be all sunshine and animal crackers when he's talking about how his mother came after him with a knife for eating an Oreo:
She had the big kitchen knife, and it was pressed to my throat. And as she laughed, I could feel it shake in her hands, and push against my skin.
She cut me that night. Just a little.
Just to teach me not to steal, and not to sneak. (2.7-9)
Matthew tells the whole story unflinchingly and without sparing any details. He doesn't sugarcoat anything. Why should he? He knows that this is how the world works… and the gritty tone of the book reflects his point of view.