What makes a life great? What is the holy grail? The north star? I have read hundreds of books, read autobiographies, studied people and societies. Observed variety of people. And did thousands of large and small experiments with my own life. And based on my experience, I’ve concluded that the secret to lead a great life (lead, not live) is sustainable happiness. Why sustainable happiness? Normally, happiness comes and goes for most people. Happiness, though a subjective concept for many, has...