One in a million
The wise men of Chelm were discussing whether one would be better off to have been born or never to have been born. After seven days and seven nights they came to their conclusion: one would be better off never to have been born, but who is that lucky? Maybe one in a million.
Here is a quotation from Agnon with the same subtext, from the last chapter of Temol Shilshom:
קל להם לאותם שאינם טורדים עצמם בהרהורים יתירים, אם מחמת תמימות יתירה אם מחמת חכמה יתירה, אבל כל מי שאינו לא תמים הרבה ולא חכם הרבה מה יענה ומה יאמר?
It's easy for those who don't trouble themselves with too much thought, either because they're too wise or because they're too simple. But someone who is not so wise and not so simple is left with nothing to say.