"The burden of coping with life's many stresses, when you have to deal with them all by yourself, it not only feels more exhausting, it literally creates more wear on your body," said Coan.
In fact, a recent CBS News poll conducted for "Sunday Morning" finds that more than 90 percent of Americans say it's important to have close friends. (62 percent said "very," and 29 percent said "somewhat," versus 8 percent who responded "not at all").
But what happens when people have trouble with their friends?
"When there is a relationship like that, you either need to resolve the ambivalence, or else make the decision that the friendship isn't worth keeping," said psychologist Irene Levine, who has become kind of the "Dear Abby" of friendship. She wrote a book about breaking up with friends, and now has a friendship blog that has drawn questions from some 200 countries, such as:
"My friend at work dumped me . . . should S keep hanging on to hope?"
"It's very hard when you have to face someone in the office every day, and you've been friends and you're no longer friends," said Levine. "You know, just like you need to work on a marriage, you need to work on a friendship."
As for whether men and women can be friends without a sexual relationship, our poll finds that 84 percent of Americans say the answer is yes. But what about differences between how men see friendships with their guy pals, versus how women view their female friends?
"I hate to put people into boxes," said Levine. "However, in general women have more intimate relationships with their friends, so they're more intense, they're more important to them."
But things are different just outside of Dallas, where Scott Prentice, John Groll, Ron Nevelow and Willie Baronet may do the usual guy things, like "trash-talking."
"It means making fun of his abilities, 'cause he can't play basketball," said Willie. "John can't play poker. Scott can't out-fish me, those sorts of things."
"I've got pictures to prove otherwise, that's all I can say," Scott retorted.
You get the point, especially when they join other friends for a game of whirlyball -- kind of a mash-up of lacrosse and basketball, played in bumper cars.
But they say that the friendship they've developed over more than 15 years is far different than the stereotypical friendship most people think of between a bunch of sports-loving, poker-playing guys.
"I've never found a group that's so understood me, accepted me, loved me, and honored me as this group does," said Scott.
"We are willing to share deeply with each other what our fears are, what's not working well, and I think most men yearn for that connection, but don't feel comfortable going after it," said Willie.
"You're all married, or in relationships; what do the women in your lives think about these friendships?" asked Braver.
"I guarantee you, without these guys, I wouldn't be married," said Scott. "I had, you know, a fear of commitment. They helped me walk through what it was that was keeping me from being able to have a wife."