Whenever I confessed to anything, it always turned out to be a bad thing. When I was a little kid, my father committed some indescretion and confessed to my mother. When I was much older, my mother brought it up. She never said just what took place, but she did say that confessing made him feel better and made her feel worse. So confessing is a selfish thing, it just hurts others when there is not a need to know.
Same with keeping a diary. Why someone would want to put something incriminating down on paper for someone else to get their hands on, I do not know.
I definitely have secrets that I will take to the grave. I will share them with no one. I sure will not write them down anywhere. No one would be better off knowing what I know. And no one can blackmail me.
Target (of the "If I told you, I would have to kill you" class)