something you must never become lax about maintaining it

"Happiness is the consequence of personal effort. You fight for it, strive for it, insist upon it, and sometimes even travel around the world looking for it. " 

Elizabeth Gilbert (Eat, Pray, Love)

学习如何快乐的生活，也是人生的一门课。但是这是一门选修课，并且许多人都觉得自己可以考满分。其实不然。