The air in a man's lungs 10,000,000,000, 000,000,000,000 atoms, so that sooner or later every one of us breathes an atom that has been breathed before by anyone you can think of who has ever lived - Michelangelo or George Washington or Moses.
I would say this to my students all the time, it's about 30% you as the teacher and 70% about them. They tend to think that their role is to be the baby bird in a nest and you're going to feed them? They're going to feed themselves, or they're going to starve.