The severest test of a character…
The severest test of a character is not so much the ability to keep a secret as it is when the secret is finally out, to refrain from disclosing that you knew it all along.
I suspect that this principle of character also applies to the ability to refrain from chiming in when someone in the room is explaining something and you can’t resist what you think is a better explanation. I know that is certainly one of my challenges.