Thanks @felt.buzz, yes, I believe that tomfoolery is very much an underused word. I've recently been considering compiling a list of words that are not used as much as they used to be, and this one feature quite high on my list. I'm just happy that someone picked up on it and actually knew what it meant!!

I'm not sure as to whether or not prison actually does what it claims too. I wonder whether there are simply too many elements at play to really see true rehabilitation. I guess, it's something that statistics will tell us about.

The self-fulfilling prophecy is an interesting one. I tend to see it from your idea. If you keep preaching to yourself that you are one thing, then eventually, you'll likely end up as that thing. I think the opposite is called affirmation. Tell yourself that you'll sin every morning, and that's what's likely to happen. Sad how some people only experience the negative.