Leonardo isn't simply saying that ungrateful people are unworthy—he's identifying a circularity of existence itself. The person who has stopped valuing life has already begun to forfeit it, not through death, but through a kind of spiritual bankruptcy that makes them incapable of receiving what life offers. When we encounter someone trapped in chronic apathy—perhaps a talented friend who sabotages their own opportunities, or a relative numbed by depression—we recognize Leonardo's observation: they're not being punished from outside; their own indifference has already become the cage. The insight cuts deepest because it suggests that worth isn't about deserving in some cosmic ledger, but about whether we're genuinely alive to the gift we've been given.