there's no fool like an old fool
口語·批評年長者的糊涂行為
例句
He fell for that scam at 70—there's no fool like an old fool.
典故來源
源自16世紀英國諺語，強調老年人因經驗豐富卻仍犯傻，比年輕人更顯愚蠢。