Every man is either a fool or a physician after thirty years of age.

More proverbs about Human Nature

• An old fool is the worst of fools. Inexperience excuses foolishness; years of repeating mistakes demonstrate willful ignoran…
• Better it is to meet a bear bereaved of her whelps, than a fool in his folly. Confronting a dangerous animal is safer than engaging with someone determined to persist…
• As the fool thinks, so the bell chinks. A fool's actions produce predictable, hollow results—noise without substance or deeper me…
• Fools set stools for wise folk to stumble at. Foolish people create obstacles that even intelligent ones may trip over through careless…
• A fool's bolt is soon shot. Reckless people exhaust their resources or arguments hastily, leaving themselves defensel…
• Fools build houses, and wise men buy them. Shrewd investors profit from others' labor and mistakes rather than bearing construction…