Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Bitter, Earnest, and Reflective
Jacob Have I Loved has all kinds of stuff going on in it, so it's no surprise there are many (sometimes conflicting) tones in the story. Louise spends a whole lot of the novel being really bitter, jealous, and disgruntled with her lot in life. The girl has some serious issues. She's resentful toward her family, her friends, and even her home:
I once dreamed that I had killed [Caroline] with my own hands. I had taken the heavy oak pole with which I guided my skiff. She had come to the shore, begging for a ride. In reply I had raised the pole and beat, beat, beat. In the dream her mouth made the shape of screaming, but no sound came out. The only sound of the dream was my own laughter. (6.6)
OK, but this doesn't mean Louise is nothing more than one big troll spewing hate at everyone she sees. While our main character might feel hateful at times, she doesn't revel in it or find any joy in disliking others—in fact, she's actually pretty ashamed of it. She can't help how she feels, though, which is why she shares her thoughts in an earnest and truthful way, while making it clear she isn't proud of her bitterness and jealousy:
I would search the Scriptures, but not for enlightenment or instruction. I was looking for some tiny shred of evidence that I was not to be eternally damned for hating my sister. Repent and be saved! But as fast as I would repent, resolving never again to hate, some demon would slip into my soul, tug at the corner, and whisper, "See the look on your mother's face as she listens to Caroline practice? Has she ever looked at you that way?" And I would know she hadn't. (6.12)
It's important to remember that this story is told by an older—and wiser—Louise as she looks back at her childhood. She's thinking back to the first summer she started to hate her lot in life, but she's not wallowing in her misery. Instead, she's exploring and reflecting on those feelings. After all, she knows things are ultimately going to work out just fine as we follow along on her journey to redemption. Because of this, the book is packed with bitterness as well as hope.