I read this book about 6 years ago I remember it being very helpful to me. They spoke on happiness in other countries and how a smile is a universal form of communication. Left brain and Right brain aspects of happiness.
Eyes open or eyes closed? it seems to me that certain asanas (pose) I find it easier to remain balanced while my eyes are open and when I close them mid asana I am wobbling all over the place. So it made me explore the reasoning behind it. I’ve learned that I am depending on sight for balance when my eyes are open. When I am depending on feel for balance my eyes are closed. Just something I realized.