In Val McDermid's "The Wire in the Blood," the author explores the idea that clichés are rooted in genuine truths about human experience. Phrases like "better the devil you know" and "don't take sweets from strangers" capture life lessons learned over time, suggesting that wisdom is often derived from collective experiences. These sayings remind us to be cautious and to value familiarity, as they encapsulate common fears and practical advice about navigating the complexities of relationships and society.

The narrative emphasizes that these adages gain their status for a reason—they resonate with shared realities that people have encountered. By referencing such clichés, McDermid adds depth to her characters and showcases their struggles with trust and danger in their lives. This approach allows readers to reflect on the importance of age-old wisdom in modern contexts, highlighting how the past informs present choices and interactions.