there's no fool like an old fool
- If a person does not develop wisdom with age, then his or her foolishness is all the more obvious and shameful; old age does not necessarily imply wisdom.
1920, Agatha Christie, chapter 1, in The Mysterious Affair at Styles:
- "You're an old woman, Emily, and there's no fool like an old fool. The man's twenty years younger than you, and don't you fool yourself as to what he married you for. Money!"
no wisdom with age