The pout-pout fish believes he only knows how to frown, even though many of his friends suggest ways to change his expression, until one day a fish comes along that shows him otherwise.

A simple shift in thinking can change everything you believe about your own happiness. By the time we become adults, most of us have joined the religion of suffering, which preaches that unless circumstances are controlled, life will be a mess. We compare ourselves to others and speculate about an impossible-to-know future, holding out hope for an improved life through getting ahead, fulfilling passion, or finding true love. But the idea that happiness...