I heard a definition once: Happiness is health and a short memory! I wish I'd invented it, because it is very true.

Hepburn credits an anonymous “definition” of happiness—“health and a short memory”—and endorses it as practically true. The line links well-being to two complementary capacities: physical vitality (health) and psychological resilience (a “short memory” that lets one release grievances, disappointments, and past pain rather than rehearse them). Her added remark—wishing she had invented it—signals both admiration for the aphorism’s elegance and an awareness of how rare it is to express a complex philosophy in a few words. The quote reflects a pragmatic, humane outlook: happiness is less a permanent state than a habit of caring for the body and refusing to be trapped by the past.