I am the only child of a perfectly functional family. My parents were devoted to God and to each other. Even though that is true, there are many things that were left unsaid or undiscovered in conversations with my parents as a grew to be an adult.
In hindsight, I have noted some of those things that I wish I had been told or that could have been elaborated on in our daily lives. As I identify those things, I assess if I am covering those bases with my own kids. I also try to find scripture to re-inforce the truth of the notion or idea (when applicable).
I bet others may have some of those things too. Please do share! It doesn't have to be profound or anything.
I'll start with a basic one: Pets die. Even if you feed them, water them, care for them and love them.