Why can’t the bank keep a secret?It has too many tellers
Never tell a parrot your secrets.

The Secret is, if revealed, not the fault of the revealer, but the person who has confided it.
The Secret is a thing a man can keep better when it is another man's than when it is his own. A woman, by contrast, can keep her own secrets better than she can others.

A Secret is powerful when it is empty. People often mention the 'masonic secret.' No one can tell what it is and as long as it remains empty it can be filled up with every possible notion, and it has power.
Did you hear about the top secret library project?It’s all very hush hush
A Secret is impossible to keep. If one's lips are silent, he chatters with his fingertips... betrayal oozes out of him at every pore.
Why can’t you trust tacos?They tend to spill the beans
The Secret is not a specifiable content, something that can one day be discovered. It is a secret without a secret.