Take a cup of kindness yet.

True kindness comes from, and generates, inner strength. It benefits not only its recipients, but its practitioners—and all of their circles of influence.

If you ask your circle what character traits relate most to business success, what do you think you would hear? Vision? Focus? Determination?

Those qualities are important, of course. But I (along with many scientists) submit that there’s another quality that should be on our “success traits” list: simple kindness.

In fast-paced, high-stress settings, many of us think of kindness as an extra: icing you add to the cake if you have the patience or time. But kindness is so much more.

Kindness is not just a nicety. It’s a powerful force. Even in the worst of times, kindness still makes things better. These things include not only personal relationships, but also physical health, esprit d’corps, and group productivity.

Nor is kindness is noblesse oblige or other condescension. Nor is it fearful self-sacrifice, nor goody-goody smugness. True kindness comes with a sense of equality. It comes from, and regenerates, deep inner strength.

By contrast, inner weakness tends to breed unkindness (which, if habitual, devolves into bullying).

The classic movie-as-parable, “It’s a Wonderful Life” (for all its fairy tale quality), clearly illustrates these ideas: George, a kind business/community leader, gets horrible business news. He feels weak and ashamed. He lashes out, hurting people close to him. But when a kind angel shows George how much good he has done, George realizes what a strong (and important, and fortunate) person he has always been.

But this isn’t just Hollywood saying so. It’s science, too. Plentiful research has shown that kind behavior releases endorphins in the brain, producing a euphoric feeling known as a “helper’s high.” You’ve probably felt those endorphins at times: when you’ve done favors for, spoken kindly to or showed concern for others.

In fact, you may be accustomed to these feelings. If so, your physical health is likely better for it. Joint research at Johns Hopkins University and the University of Tennessee has found that people who helped others reduced their own blood pressure. They also reported “greater self-esteem, less depression and less stress.”

Scientists also tell us that being kind relates to ourprimal survival instincts. Millennia ago, humans’ dependence on each other was understood. To our ancestors, it was obvious that caring for others was vital to group cooperation, safety and ultimate survival.

So why aren’t people kinder? Why do we so often override our natural instincts for kindness? For one thing, kindness rewards the highly evolved parts of our brain. But in our primitive, reptilian brains, the dominant instincts are fright and flight. And our reptilian brains tend to take over in moments of shock or great stress.

Also, culturally, we Americans tend to acclaim individuality over team spirit, competition over cooperation. This cultural atmosphere tends to reduce our awareness of others’ needs: that is, opportunities to be kind. As a result, we lose touch with the kindness instinct. We forget how good kindness feels. We begin to feel disconnected, frightened and weak—as George Bailey did.

Add kindness to your skill set. Being kind, not only to others but also to ourselves—is a strength we can learn and improve. Try this exercise to start feeling calmer, kinder, more connected and healthier soon.

Four-star general and Secretary of State Colin Powell credits kindness for much of his success. He counts kindness among the key skills of the best drill sergeants, and has said, “Being kind doesn’t mean being soft or a wuss. Kindness is not a sign of weakness (but of) confidence.”

That confidence—that strength—explains the effortless quality to a life lived with kindness. It opens the door to a vast and satisfying way of being, in which we can succeed without others having to fail. It helps us build supportive, satisfying relationships. It allows us to accept human foibles in others, and also in ourselves.

All told, kindness is central to our mental, emotional and social health—and our overall success.

How have you experienced kindness as a giver? As a recipient? How did these experiences affect you?

As always, I welcome your stories.