The most trivial things can build the strongest relationships. Even though I've never lived in Chicago, I have a soft spot for the Cubs. My father grew up in the Windy City and loved the team his whole life. And I loved my dad. So, by the transitive property, I loved the Cubs too. Two decades after my father's death, I am still a fan. Every time I watch the Cubs on television, I think of him and have a conversation with him in my head about the game.

Perhaps baseball strikes you as too trivial a thing for father and son to connect over. Maybe we could have bonded more through our shared vocation (I am an academic, like he was–and like his father was too), or our feelings toward our relatives. Compared with family and career concerns, a ball game might seem, frankly, sort of useless.

But that is precisely what makes it ideal for forming relationships. In a transactional world, our relationships with others tend to become part of a web of useful alliances. But such alliances make for the least satisfying relationships. If you are finding that your closest bonds of friendship and family leave you feeling empty, the solution is not to make your relationships more practical. It is to organize them more around things that aren't useful at all–like baseball.

When it comes to understanding our relationships with others, for my money, the best source is Aristotle. He wrote extensively about the many types of philia, or the mutual attraction and attachment that form the basis of every relationship between human beings. Philia based on transaction is the least virtuous kind, according to Aristotle. For example, I am friendly with my dentist, and she is friendly with me, which makes it less unpleasant for me to give her hundreds of dollars to drill my teeth. At the other end of the spectrum is philia based simply on the deep satisfaction that a relationship brings to each person in it, and a desire that the other be happy. They "wish each alike the other's good," Aristotle wrote.

p class="ArticleParagraph_root__wy3UI">This highest philia often includes a common love for a third thing, such as religious faith or a search for moral perfection. I have one close friendship, for example, in which my friend and I frequently discuss our efforts at improving ourselves as people. But as research has shown in the more than 2,400 years since Aristotle described philia, a mutual love doesn't have to be for something profound in order for it to bolster a deep friendship. Just as the highest philia is not "useful" in a worldly sense, the love that sustains it can be for something that might seem trivial. The point is that it brings friends together in shared satisfaction, without being transactional.

And this brings me back to the Cubs, the team that brought me together with my dad, and that still brings me happy memories of the love between us long after his death. We had nothing to gain as we watched them play, except for the satisfaction of enjoying the games together as father and son, a satisfaction that was much greater than it would have been had either of us watched without the other. The Cubs were the "place" where we met to enjoy our bond.

Lots of sports fans have similar experiences. In their forthcoming book, Fans Have More Friends, the sportswriters Ben Valenta and David Sikorjak find that the biggest enthusiasts have the best social lives. The authors measured the intensity of one's love for sports–they call it "fandom"–by people's self-rated passion as well as the time they spend watching and participating; they then compared that with the quality of people's friendships and family life. The relationships are correlative but striking. For example, 42 percent of the most involved sports fans were "very satisfied" with their family life, compared with less than a quarter of nonfans. Sixty-one percent of fans, but only 37 percent of nonfans, said they "felt close to people."

These findings are consistent with past research on sports fans. Scholars have found that both fandom and fan loyalty are positively associated with a sense of belonging and a sense of meaning. One study from last year showed that active sports participation actually causes greater life satisfaction. And in a 2009 study of 900 people who played sports in the Netherlands, a third said that they "generated their social networks, their self-esteem and trust in others primarily through sport." Sports are just one example; research shows that people bond in meaningful ways over all kinds of impractical things, from classic cars to birdhouses to cheesy TV.

If your relationships with friends and family are leaving you a little cold, you might be suffering from excessive usefulness in your activities. Maybe the solution is cultivating a taste for baseball, or maybe instead for opera, chess, or Jeopardy. No matter what your friendship-boosting hobby is, be sure to follow two rules.

1) Make it intrinsic, not instrumental.

Remember that Aristotle's perfect philia requires you to focus on the inherent satisfaction you get from someone's company, not worldly gains such as money or career advancement. Your pastime should mostly serve that satisfaction goal. Maybe you can share enjoyment of a professional pursuit with a friend, but be careful–goals can shift quickly and imperceptibly. What was primarily an excuse to spend time with a loved one and secondarily a professional venture can easily become more business than fun. An unprofitable pursuit is a safer bet.

2) The point is philia, not passion.

If I am to be truthful with you, I am not authentically passionate about any pastimes, and I never have been. I envy people who honestly seem to love college football, whittling, or singing in a community choir, because I am not one of them. That doesn't stop me from achieving perfect philia, however. You can still form a bond with someone you appreciate by dabbling in something you like but don't love. To cultivate better philia, don't pretend to enjoy something you really hate. But do consider what your loved ones enjoy, and if those interests appeal to you at all, you can adopt them by choice.

When my father died, I stopped watching baseball for a while. I had little kids, was busy building my career, and had no time. But really, the reason I was no longer a fan was that if I watched a game, I'd want to talk about it with only one person, and he was gone. After a few years, I realized this was a mistake: The Cubs could bring my dad back.

In February, I gave a talk about workplace happiness to the Cubs front-office staff at Wrigley Field. Afterward, I imagined what my dad would have said–and how it would have had nothing to do with the work I'd done. "Did they say anything about their pitching?" he would have asked instead. "Trading Yu Darvish and letting Jon Lester escape in free agency last year was brutal. But a lot of the young arms this year could be great!"

And just like that, we were together all over again.