Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Matter-of-Fact
Jack London's not one for putting on fancy pants. He likes to give you the facts, and let you make the call. Even when we're close to White Fang, it's not like we're swept up in a whirlwind of emotions:
But the bane of his life was Lip-lip. Larger, older, and stronger, Lip-lip had selected White Fang for his special object of persecution. White Fang fought willingly enough, but he was outclassed. His enemy was too big. Lip-lip became a nightmare to him. (10.7)
Lip-lip sounds scary as all get-out, but it's not like London's describing him as the devil incarnate. There's no emotion here—just facts. The closest he gets to emotional is "Lip-lip became a nightmare to him," but even that's pretty matter-of-fact.
London asks us to get close to White Fang not by dropping us knee deep in his feelings, but by allowing us to stick with him. Eventually, we can't help but root for the wolf-dog, because we've been with him every step of the way. London doesn't want to emotionally manipulate us. He relies on the events to speak for themselves.