In Ian McEwan's novel "Nutshell," the quote "Don't unpack your heart. One detail tells the truth" emphasizes the importance of emotional restraint and the significance of carefully selected truths. The idea suggests that revealing too much of one’s feelings can lead to vulnerability, while focusing on a singular, telling detail can convey deeper truths without overexposure.

This perspective invites readers to consider the complexity of communication and the ways in which a single piece of information can encapsulate broader emotions and realities. It encourages a reflective approach to understanding oneself and others, highlighting the power of subtlety over overt emotional expression.