Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Pushing Through Tragedy
The tone of The Usual Rules can be pretty somber at times because Wendy is going through a particularly difficult time—after all, she's dealing with a national and personal tragedy. Throughout the book, Wendy tries to cope with her mother's death and her own feelings of guilt over having been a "bad daughter," and this colors the whole story. In fact, Wendy even says at one point that color no longer exists in her world:
All this time, Wendy still hadn't cried. She thought it might be a relief, but she couldn't do it. The dull Novocain sensation that had begun taking hold that Tuesday had overtaken her now. The whole world, everything around her, had turned flat and colorless. (3.225)
This same colorless despair comes across in the tone of the book. There's a neutrality to the tone, a sort of depressed and flat feeling that comes up time and again. Check this passage out for another example:
Even Amelia, as talkative a person as she was, must have known there was nothing to say. The two of them lay on the floor, holding each other, until very gradually the crying slowed to where it was only long, sad sighs. Then, finally, quiet. Even after that, they just lay there awhile.
Maybe we should have some Haagen-Dazs, Amelia suggested. It seemed as good an idea as anything else. (3.230-231)
There's nothing melodramatic about this scene. It doesn't play up Wendy's pain—it's big enough on its own. And then when Amelia suggests ice cream, the response is pretty neutral: "It seemed as good an idea as anything else" puts pretty much everything in the world on the same level. Nothing is wonderful, nothing is terrible; everything simply is. This mirrors the flatness of depression really well, infusing the book with the dominant emotion Wendy feels.