Happiness Vs. Purpose
So what good is doing something that matters, being productive, being useful, and making a difference, if one is not happy in the process? Why would / should a person do these things if not to be happy?
How would one know what his purpose is, other than by observing the happiness or sadness that various pursuits produce? Happiness, or more precisely, our perception of it, is a sort of guide for us; a compass if you will. By trying various activities, and then noting how each one makes us feel, we zero in on our purpose by pursuing what makes us happy, and avoiding what makes us sad or bored.
When we occupy ourselves in ways that make us truly happy, then I propose that we’ve discovered our true purpose (if there is even such a thing as true purpose, and I’m not convinced that there is). Without our good and bad emotions to show us the way, I submit that it would be impossible for us to learn our true purpose.
So be careful not to underestimate the role of happiness. IMHO: Happiness is indeed the ultimate object of life. That other stuff (making a difference, leaving something good behind, and so on), is the means we have to reach happiness and complete fulfillment.