Optimism sets a different machine in motion. Especially in difficult moments, the people you lead need to feel confident in your ability to focus on what matters, and not to operate from a place of defensiveness and self-preservation. This isn’t about saying things are good when they’re not, and it’s not about conveying some innate faith that “things will work out.” It’s about believing you and the people around you can steer toward the best outcome, and not communicating the feeling that all is lost if things don’t break your way. The tone you set as a leader has an enormous effect on the people around you. No one wants to follow a pessimist.

The more you explain bad events as temporary, specific, and external, the more likely you are to persist even in the face of adversity.

Without negativity you . . . lose touch with reality. You’re not genuine. In time, you drive people away.” So allow yourself what she dubs “appropriate negativity

But the successful seller must feel some commitment that his product offers mankind as much altruistic benefit as it yields the seller in money.

A friend once said of my earlier work that I wrote with a signature of “well-founded hope.” The mountains of systematic research, combined with my dedication to drawing insights from the evidence, provided the “well-founded” part. “But the message is always hopeful,” he said. “You demonstrate with evidence that good can become great, that people can build organizations worthy of lasting, that strong values can win in a hypercompetitive world.” Well-founded hope. This study only added to that signature for me. It made me feel even more hopeful and optimistic, not directly about the world at large, but about people. And people, after all, make the world.