I'm reading Casanova's Memoirs right now. I thought this was really insightful -
The theory of morals and its usefulness through the life of man can be compared to the advantage derived by running over the index of a book before reading it when we have perused that index we know nothing but the subject of the work. This is like the school for morals offered by the sermons, the precepts, and the tales which our instructors recite for our especial benefit. We lend our whole attention to those lessons, but when an opportunity offers of profiting by the advice thus bestowed upon us, we feel inclined to ascertain for ourselves whether the result will turn out as predicted; we give way to that very natural inclination, and punishment speedily follows with concomitant repentance. Our only consolation lies in the fact that in such moments we are conscious of our own knowledge, and consider ourselves as having earned the right to instruct others; but those to whom we wish to impart our experience act exactly as we have acted before them, and, as a matter of course, the world remains in statu quo, or grows worse and worse.
Casanova likens learning morals before getting real world experience to reading the index of a book before the book itself. You get an idea of what's going to be in the book, but you don't really "get it."
It's kind of subtle, but I laughed a lot at him saying everyone feels the need to against what they were taught, have things go badly because of their choice, but then they feel consoled that they can now teach others. Hilarious stuff.
I'm enjoying Casanova's Memoirs. Interesting book. It's out of copyright, and thus free at Gutenberg.org - here's the first section in plain text - http://www.gutenberg.org/cache/epub/2951/pg2951.txt