Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Disenchanted, Sarcastic, Contemptuous, Hopeful
When Daisy arrives in England, she's a sassy, jaded little teenage punk with attitude, and this comes across in her storytelling, where she constantly compares England to New York. For instance:
I'm not exactly in the habit of having people take over a perfectly private house to send the inhabitants off to god knows where for The Duration, and all I could think was this would not happen in America. (1.14.3)
Yeah, someone's not having it. Thing is, even as life get dicey in war-torn England, Daisy doesn't lose her sardonic narration. At one point, she even says:
Ages ago I learned in social studies about how the Cavemen and the Bushmen and other Primitive Tribes spent every waking hour searching for food and it was nice to be able to draw a good straight line through history between Hairy Old Neanderthal Man and us. (1.28.3)
To be clear, Daisy's making a joke about starvation here—in the form of the ability to willingly starve being some sort of marker of evolution/progress. Lest you assume Daisy's just totally given up on life though, it's important to note that even when things are at their absolute worst (like when she literally encounters a field of dead bodies), she manages to keep hope alive. Dreams about seeing Edmond again and "living some sort of life" are woven throughout, making it clear that no matter how much contempt Daisy has for her current situation, she believes that there's a light at the end of the tunnel.