For the most part, the tone of the novel is playful, excited, and lighthearted. Often, it seems as though Tolkien imagines that he is telling an adventure story to a group of children seated at his feet. One example occurs in Chapter 2, when Bilbo picks the pocket of one of the trolls:
Bilbo plucked up courage and put his little hand in William’s enormous pocket. There was a purse in it, as big as a bag to Bilbo. “Ha!” thought he, warming to his new work as he lifted it carefully out, “this is a beginning!”
It was! Trolls’ purses are the mischief, and this was no exception. “’Ere, ’oo are you?” it squeaked, as it left the pocket; and William turned round at once and grabbed Bilbo by the neck, before he could duck behind the tree.
This might easily be a scary scene. It is certainly suspenseful and high-stakes. Tolkien emphasizes Bilbo's "little hand" and "plucky courage" compared to the trolls' "enormity" and self-assured strength. These descriptors turn Bilbo into a character with whom children or adults who have ever felt powerless can easily identify. Bilbo hardly stands a chance against these hulking enemies. The moment when William "grab[s] Bilbo by the neck" might elicit a gasp as readers wonder how the hobbit will manage to survive. At the same time, Tolkien uses a playful tone to reassure the reader that they need not be too scared. In a book where a purse figuratively "squeaks" in a Cockney dialect upon being lifted out of a pocket, surely everything will turn out okay. Sure enough, Gandalf comes to the rescue and no one but the Trolls get hurt.
Again and again, Tolkien puts Bilbo in dangerous situations but finds ways to reassure the reader not to take the danger too seriously. For instance, he repeatedly writes that Bilbo will always remember the experience he is about to have. This commentary makes clear that Bilbo will live a long life after his adventure is over. He is never truly in danger of dying, even if he sometimes thinks he might be.
Tolkien's lighthearted storytelling helps him turn what could be a traumatic story into a tale about adventure and the development of a hero. As a veteran of World War I, Tolkien endured war without the prior knowledge that he would live to tell the tale. In contrast, he makes sure to tell Bilbo's story with the benefit of hindsight. The Hobbit thus becomes evidence that sometimes, when a person stretches their comfort zone just far enough, they can surprise themselves with their own strength.