At the beginning of the novel, Gene is thinking about how his perspective on things and people has changed since his childhood. He uses hyperbole as he compares the "giants" of his childhood to how he sees his teachers and family members as an adult:
[T]hose men, the giants of your childhood, whom you encounter years later and find that they are not merely smaller in relation to your growth, but that they are absolutely smaller, shrunken by age…[for] the old giants have become pigmies while you were looking the other way.
The hyperbole describing adults as "giants" during childhood points to the awe children often feel toward adults. It conveys how children and teenagers sometimes see adults as larger-than-life figures. By exaggerating their size and significance here, Gene emphasizes how his own youth and size affected his perspective. When he returns to the Devon school, he recalls how these "giants" loomed over his childhood. They seem huge in his memory because they shaped his understanding of the world and his place within it.
By contrast, these adults seem much smaller and less important when Gene is grown up. Knowles’s hyperbole in calling adults "pigmies"—an outdated and pejorative term that refers to a central African ethnic group in which adults are short-statured—instead of “giants” is a way of illustrating this shift. The adults seem smaller not only physically, but also in influence and importance.
Because Gene worries so much that Finny is his social and moral superior, he’s astonished when he realizes the jealousy between them might go both ways. Knowles uses hyperbole and similes to convey Gene's shock and realization when, in Chapter 4, Finny reveals he’d be jealous if Gene became Head Boy:
In front of my eyes the trigonometry textbook blurred into a jumble. I couldn’t see. My brain exploded. He minded, despised the possibility that I might be the head of the school. There was a swift chain of explosions in my brain, one certainty after another blasted—up like a detonation went the idea of any best friend, up went affection and partnership and sticking by someone and relying on someone absolutely [...]
Gene is using hyperbole when he says that his “brain exploded" here—his brain is fine, he’s just so astonished that Finny could be jealous of him that he doesn’t know what to do. The realizations of Finny’s disloyalty that come after this also behave like "a swift chain of explosions in [his] brain." Gene is absolutely overwhelmed by the realization that Finny is jealous of him. He’s shocked and disoriented but also intensely disappointed because it disrupts his confidence in Finny’s love for him.
The simile in this passage also refers to explosions. Finny admitting he would be jealous if Gene became Head Boy feels very destructive to Gene. He feels that his certainties of “affection and partnership” have been “detonated” and exploded. His previous assumptions about Finny’s friendship and loyalty are violently shattered.
In Chapter 6, Gene encounters a figure approaching him on one of the Devon School's paths and instantly feels afraid. In this passage, Knowles uses a simile and hyperbole to create an atmosphere of unease:
Someone was coming toward me along the bent, broken lane which led to the dormitory, a lane out of old London, ancient houses on either side leaning as though soon to tumble into it, cobblestones heaving underfoot like a bricked-over ocean squall—a figure of great height advanced down them toward me.
This highly figurative and exaggerated description of the setting points to Gene’s fear and sense of vulnerability as the figure approaches. His simile comparing the cobblestones to "a bricked-over ocean squall" links the physical environment to the unease Gene is trying to conceal within himself. Like an ocean trapped under cobblestones, he’s barely containing the disturbances below his surface. The lane seems almost supernaturally narrow and the buildings around it threaten to topple down onto him, heightening Gene’s feeling that his environment is suddenly a threat. The hyperbole Knowles employs to describe the "leaning" houses and the narrow, broken lane also contributes to the reader’s understanding of how unsafe Gene feels. He’s so scared that the solid space around him seems about to collapse.
While the Devon School is idyllic in summer, in the harsh New England winters its rural remoteness make it feel like a prison between autumn and spring. In Chapter 9, as Gene describes this feeling of entrapment and the change in the school’s atmosphere after Leper enlists, he employs imagery, a metaphor, and hyperbole:
And these Saturdays are worst in the late winter when the snow has lost its novelty and its shine, and the school seems to have been reduced to only a network of drains. During the brief thaw in the early afternoon there is a dismal gurgling of dirty water seeping down pipes and along gutters [...] Shrubbery loses its bright snow headgear and stands bare and frail, too undernourished to hide the drains it was intended to hide.
The unpleasant visual imagery of this passage brings home the dreary, decayed winter landscape at the Devon School for the reader. Descriptions of "dismal gurgling of dirty water seeping down pipes and along gutters," along with the "gray snow crust" and "frozen mud," make the school seem like a profoundly barren and unpleasant place.
The metaphor describing the school as "a network of drains" contributes to this passage’s sense of lifelessness and stagnation. Rather than being a lively place of learning, the school has become nothing more than a frozen sewer. It merely channels away waste, making Gene feel “dismal.” The other metaphor of the "bright snow headgear" of the "bare and frail" shrubs further highlights the desolation. The leaves and berries of the plants have disappeared, leaving only skeletal shapes remaining. The hyperbole in this passage exaggerates Gene’s sense of dreariness and discomfort, making each dismal Saturday seem even more unbearable.