I used to think happiness was an event. Something that would occur after I acquired something or got something done. I believe external events would cause happiness. But my exercises in Quantified Self have revealed that as in statistics, when it comes to happiness correlation is not causation.
When certain conditions are in place happiness is more likely to occur, but those conditions do not cause happiness. If I buy that new car it might contribute to a variety of conditions that elevate my mood, but acquiring the car does not create happiness.
Unlocking these relationships is the purpose of my work in Quantified Self.