Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Nostalgia Overload
Because much of Hotel on the Corner of Bitter and Sweet deals with Henry Lee's memories of his childhood, particularly his first love, the entire book is tinged with nostalgia and loss. For example, when Henry watches items being pulled out of the Panama Hotel's basement, he's flooded with memories:
The more Henry thought about the shabby old knickknacks, the forgotten treasures, the more he wondered if his own broken heart might be found in there, among the unclaimed possessions of another time. Boarded up in the basement of a condemned hotel. Lost, but never forgotten. (1.18)
It's obvious that this story isn't being told in a clinical, unemotional tone—it's full of wistfulness and strong emotions. Notice the sentimental words tucked into the above passage: "treasures," "his own broken heart," and "never forgotten." The book is filled with language like this, reminding readers the hard though life may be at times during Henry's childhood, he's ultimately quite fond of these early years with Keiko.