Men, like nails, lose their usefulness when they lose direction and begin to bend.

Landor’s aphorism compares human character to a nail: a nail is useful because it is straight and driven toward a purpose; once it bends, it can no longer hold fast or be driven effectively. Applied to people, “direction” suggests steadiness of aim, principle, and self-command—qualities that allow one to be relied upon. “Begin to bend” implies yielding to pressure, compromise, or distraction until one’s integrity or resolve is warped. The saying reflects a moralistic, classical strain in Landor’s thought: usefulness is tied not to mere talent but to firmness, consistency, and purposeful conduct.