During the events leading up to Finny's accident in A Separate Peace, Gene's acute sense of competitiveness strains his relationship with his friend Finny.
Gene feels that he consistently fails to measure up to Finny's athletic ability and charm. Even though Gene is very academically gifted, he wants what Finny has--and pushes himself to achieve it. His growing resentment of Finny's talent and subsequent need to compete to prove himself is evident in Chapter four as the boys go back and forth on why Gene studies so hard. Finny points out that it's because Gene "want[s] to be head of class, valedictorian, so [he] can make a speech on Graduation Day" (43).
Gene secretly concludes to himself that this "was a pretty good goal to have," realizing that if he were the top academic student, then he and Finny would be "even, that was all" (43). In Gene's mind, he perceives the possibility that Finny "minded, despised the possibility that [he] might be the head of school."
The thought that Finny might be sabotaging his academic efforts hits Gene hard. Knowles uses a bomb metaphor to relay the destructive power of Gene's negative thinking:
"like a detonation went the idea of any best friend, up went affection and partnership and sticking by someone" (44-45).
Gene's competitive need to prove himself against Finny breeds resentment and self-doubt of the genuinity of their relationship.