One word, 9 letters.
Happiness. H-A-P-P-I-N-E-S-S.
That's all there is to it. No matter your vocation, no matter your aspirations, the one goal is to be happy. From the preacher hoping to bring peace to the ailing elderly, to a vagabond receiving a 5 dollar bill - the one thing that drives us is happiness. Is money what makes you happy? Sure, fine - go get that high-paying job and make it happen. Family - is that what makes you happy? Should it be, then the proof is in the pudding.
Happiness is the journey - its heart lies in the performance of actions that converge along a path to what brings you personal satisfaction. Where, the operative word is personal. Whatever makes you feel fulfilled, makes you feel fulfilled - no one can stand there and tell you what does or doesn't make you satisfied. Your quest is your quest - and the footsteps you take have to be pressed by the soles of your own shoes. As you move through this life, strive to keep within the rails of your path to happiness - or don't. What ever brings you satisfaction. The key, then, is to figure out what makes you happy, and how you can build a 60+ year life out of it. For me, I find happiness in helping people. Somewhere along the line, I realized that I can best help the world through the pursuit of a career in teaching.
The goal is the journey. The journey is yours to take. I find that acting on happiness has worked for me throughout my ever-so-short time here on earth. When faced with a big choice, stop and ask yourself - what makes me happy? Separate everything else from the equation and truly ask yourself - what decision will lead to the most happiness in my life?