The main take away I left with after reading this book is that God is the only person who leave you feeling full. Looking for happiness through power, approval, achievement, money or beauty won't leave you with the same fullness as God can leave you with. Searching for empty promises really only makes you tired and always longing for something more.
I highly recommend this book if you are looking for a good Christian read before school starts back. It will make you remember the real reason you chose to become a teacher because I doubt it was for the money, the approval of others or any other empty promise.