In Jodi Picoult's novel "Leaving Time," the author explores the fragility of human intentions and the emotional turmoil that can arise from seemingly minor setbacks. The metaphor of a "hairline crack" signifies how small issues can escalate, leading to significant problems if left unaddressed. This suggests that even with good intentions, one might not withstand the pressures of life, ultimately resulting in emotional breakdowns.

The quote highlights the vulnerability of individuals when faced with challenges. It indicates that it is not just the major crises that can derail us but also the subtle strains that might go unnoticed until they culminate in a larger issue. Through this lens, the narrative emphasizes the importance of acknowledging and addressing our emotional states to maintain resilience against life's inevitable trials.