Review sites like Yelp can be a double-edged sword. On the one hand, they allow individuals to express themselves and give honest feedback about local businesses. On the other hand, they can put a lot of power into the hands of people who arguably shouldn't wield it. 

In November of 2019, San Diego doughnut shop Nomad Donuts got a one-star review on Yelp--the worst rating possible. Why? Not because of the quality of the doughnuts, but because the reviewer didn't like that Ray, a homeless man, tended to hang around the establishment.

Ray was well-known to the doughnut shop owner and its regulars. He was known for being respectful, low-key, and unobtrusive. He was a part of the shop's community, even if he wasn't able to make purchases.

This obviously put the owner, Brad Keiller, in an uncomfortable position. "The customer is always right" would require him to throw Ray under the bus, so to speak--and he didn't want to do that. But he also wanted to acknowledge the review (and the reviewer).

So he chose to respond in a unique way. To the one-star reviewer, he said:

"I understand how you feel, it's not easy to look at. I know I probably lose some business, possibly yours too, because of my choice not to chase him away but I won't. He's not looking for handouts and he tries not to bother anyone. If you stop and talk with him maybe you'll come to like him too."

This was a risk. Not only in terms of that one customer's reaction, but because Yelp is a public forum. Everyone could see what Keiller said, and it would be up to those individuals to judge the whole encounter, top to bottom. Would Keiller lose business because of the interaction? Would it cause backlash of some kind?

Quite the opposite, as it turned out. The post went viral. People were (understandably) disappointed by the reviewer's lack of compassion, and proud of Keiller for standing up for Ray.

To me, the brilliance of Keiller's Yelp response wasn't just that he backed up Ray. It's that he also found a way of acknowledging the customer's experience.

Keiller wasn't defensive or snarky or mean-spirited. He found a tactful way to say that homelessness is a difficult thing to bear witness to without saying that there was anything wrong with Ray himself. In fact, he stood up for Ray in a sensitive and graceful way.

And instead of the bad review damaging Keiller's business, the interaction as a whole led to more customers than ever--especially after the viral post was picked up by local news sites. 

One subsequent reviewer remarked: "I buy donuts and other breakfast for my team meetings. I read the article regarding the homeless man Ray, thank you for doing that. I will be supporting your business and telling others about it as well! More of this San Diego!"

As for Ray, his personal response was poignant: "I'm flattered overwhelmed by [Brad's] kindness. Wow, someone stood up for me cause I don't get that a lot."

Compassion at work is underrated. 

In fact, social science proves that it's a central part of high-quality leadership, and the glue that holds a team together. Genuine compassion for customers is also the difference between a massively effective marketing campaign and one that falls flat.

It's also worth noting that compassion itself is not a fixed trait--it's trainable. According to a 2018 study by Richard J. Davidson, a professor of psychology and psychiatry at the University of Wisconsin-Madison's Center for Investigating Healthy Minds, compassion can be "exercised," like a muscle.

Davidson conducted a study to see whether everyday people could learn to feel compassion for different kinds of people, including the "challenging" people in their lives.

He and his team had study participants complete an online meditation training for 30 minutes a day, learning to focus on feeling compassion toward others. After just two weeks, their brain scans showed elevated activity for altruistic behaviors. Plus, the study participants were more likely to behave generously with strangers.

"These findings suggest that compassion is a trainable skill," said Davidson, "and that practice can actually alter the way our brains perceive suffering and increase our actions to relieve that suffering." 

Here's even more good news: Compassion is contagious. That's right--according to research published in 2010 by Nicholas Christakis, a professor of social and natural science at Harvard University, and James Fowler, a professor of political science and medicine at the University of California San Diego, if you're kind, those around you are more likely to act kindly, too.

In short, compassionate behavior is contagious: it spreads around you, multiplying its benefits--especially for the leaders who make a point of instilling it.

So be nice. It turns out it's good for your soul and your bottom line.

Correction: An earlier version of this article omitted the title and departments for Richard J. Davidson and the year of his 2018 study. He is a professor of psychology and psychiatry at the University of Wisconsin-Madison's Center for Investigating Healthy Minds. The article also omitted the title, departments and universities for Nicholas Christakis and James Fowler and the year of their 2010 study. Christakis is a professor of social and natural science at Harvard University and Fowler is a professor of political science and medicine at the University of California San Diego.