Love Is Really All That Matters:

It may seem obvious, but that doesn’t make it any less true: Love is key to a happy and fulfilling life. As Vaillant puts it, there are two pillars of happiness. "One is love," he writes. "The other is finding a way of coping with life that does not push love away."

Vaillant has said that the study's most important finding is that the only thing that matters in life is relationships. A man could have a successful career, money and good physical health, but without supportive, loving relationships, he wouldn't be happy ("Happiness is only the cart; love is the horse.").

Connection Is Crucial:

"Joy is connection,” Vaillant says. "The more areas in your life you can make connection, the better."

The study found strong relationships to be far and away the strongest predictor of life satisfaction. And in terms of career satisfaction, too, feeling connected to one's work was far more important than making money or achieving traditional success.

"The conclusion of the study, not in a medical but in a psychological sense, is that connection is the whole shooting match," says Vaillant.

As life goes on, connections become even more important. The Grant Study provides strong support for the growing body of research that has linked social ties with longevity, lower stress levels and improved overall well-being.

Challenges –- and the Perspective They Give You -- Can Make You Happier:

The journey from immaturity to maturity, says Vaillant, is a sort of movement from narcissism to connection, and a big part of this shift has to do with the way we deal with challenges.

Coping mechanisms -- “the capacity to make gold out of shit,” as Vaillant puts it -- have a significant effect on social support and overall well-being. The secret is replacing narcissism, a single-minded focus on one's own emotional oscillations and perceived problems, with mature coping defenses, Vaillant explains, citing Mother Teresa and Beethoven as examples.

“Mother Teresa had a perfectly terrible childhood, and her inner spiritual life was very painful," says Vaillant. "But she had a highly successful life by caring about other people.

Creative expression is another way to productively deal with challenges and achieve meaning and well-being.

"The secret of Beethoven being able to cope with misery through his art was when he wrote 'Ode to Joy,'" says Vaillant. "Beethoven was able to make connection with his music."