I have a little book where I occasionally will write down little aphorisms, that I hear or that I make up. I found the germ of the following that I’d made up last fall. I’ve made some changes to it and thought it sounds very… aphoristic.
“I have made the realization that happiness is not a mental state. It is not something that is given to you, or that you find, or that you can lose, or that can be taken from you. Happiness something that you do. And like most things that you do, it is volitional. You can choose to do happiness, or not. You have complete freedom with respect to the matter.”
Really, I should point out that this insight partly derives from studying the Korean Language. In Korean, the predicate “to be happy” is “행복하다” literally means “to do [or to make] happiness”. When you say “행복해요” (“I am happy”) what you’re really saying is “happiness [I] do.” “행복한 사람” (“a happy person”) is literally “happiness doing [who-is] person” (taking into account the almost exact reverse word-order compared to English).