How much sleep you need.
The importance of cooking for yourself. Unless you hate cooking. Then never underestimate the importance of making friends who love cooking for you.
The transience of every single emotion you ever have.
What can be achieved in 15 minutes. A 'phone call, a room tidy, a home cooked meal, a bullet-pointed article or lecture plan, a yoga practice, the washing up, a list. A blog post.
The sheer joy created by growing one - one! - bright red cherry tomato.
The benefit of ten minutes on the mat.
What you mean to other people.
The satisfaction of de-cluttering. Even if it's only jettisoning 3% of your entire book collection. What? I might re-read them all again. I really might.