In Ian McEwan's novel "Saturday," the state of a person's nails serves as a metaphor for their overall well-being. As individuals face life's challenges and begin to unravel, the neglect of personal grooming, particularly nails, reflects their internal struggles and deteriorating mental state. This observation suggests that small details can reveal much about a person's emotional and psychological health.

The quote emphasizes the connection between outward appearance and inner turmoil, highlighting how life’s pressures often result in a decline in self-care. McEwan uses this imagery to illustrate the effects of stress and chaos on an individual's life, subtly conveying the message that even minor signs, such as unkempt nails, can indicate deeper issues at play.