The quote by Washington Irving highlights a timeless truth about personality traits, suggesting that a bad temper does not improve with age. Instead, individuals who possess a sharp wit or a quick tongue only become more adept at using them over time. This can lead to more intense conflicts and misunderstandings as these qualities, rather than softening, can exacerbate situations.

In M.C. Beaton's work "Death of a Nag," this theme likely resonates with the characters and their interactions. The sharpness of one’s demeanor may create tension, reinforcing the idea that temperamental individuals often remain set in their ways, making reconciliation and understanding challenging as they mature. Ultimately, the quote serves as a reminder of the enduring nature of certain dispositions throughout life.