In John Updike's short story "A&P: Lust in the Aisles," the protagonist, Sammy, navigates a pivotal moment of moral choice when he witnesses a situation involving three young women in the local grocery store. His impulsive act of quitting his job to defend their honor illustrates a youthful rebellion against societal norms and expectations. However, it also highlights the complexities of standing by one's decisions.

The quote, "But it seems to me that once you begin a gesture it's fatal not to go through with it," encapsulates the theme of commitment to one's actions. Once Sammy makes his bold move, he feels an obligation to see it through, emphasizing the significance of integrity and conviction in personal choices. This moment foreshadows the consequences he will face, leaving him to contemplate the costs of his impulsive decision in a world that often rewards conformity.