According to the book I’m reading (The Happiness Trap), the secret to a fulfilling life is living in full alignment with one’s values. The idea is that many people (most people?) don’t think about what they most value in the world, and therefore don’t live in a way that they find truly fulfilling. Further, the theory goes that if you do start living in alignment with your true values, you can overcome emotional challenges much more easily.
I’m working on trying to identify my values, but it’s harder than I thought. I have never really given much thought to it.