Exactly two weeks from today is the release of my third book, The Gift of Influence. For a lot of my peers on the speaker’s circuit, writing three books in a dozen years isn’t that impressive. Some of them can pump out a book per year like clockwork. But it takes me a long time to pour my heart onto the page, which is why I’m so excited to share The Gift of Influence with the world on September 20. It’s about how to create a life-changing impact in your everyday interactions. Once you realize you have the power to positively change the lives of others—even complete strangers—you never look at the world again the same.

But here’s the catch: You must be intentional. When you are confronted with an opportunity to change a life, you can’t walk on by.

Last week, my wife, Jill, and I dropped our fourteen-year-old son Tate off at Shattuck-St. Mary’s hockey boarding school in Faribault, Minnesota. After boarding school, he’ll go to college, and after that, he’ll begin his adult life, so Tate will never again be living with us full-time. As we helped Tate move in, this realization seemed to hit us all at once.

All my friends and family know that I’m a crier. I’m famous for it. I cry at everything from Hallmark cards to movies like The Notebook. Crying makes me feel alive. But today, I wanted to be strong for Jill and Tate. I wanted them to know that even though Tate was leaving home, he would never be leaving our hearts. That even though he was eight hundred miles away, we would never be closer as a family.

Jill and I lingered in that dorm room for a long time, finding something to organize, reminding Tate about his schedule for the umpteenth time—anything to avoid saying goodbye. At long last, we ran out of excuses, and we hugged Tate one last time. It took everything I had to keep those tears in. When you leave your child behind in a strange place, that deep reptilian region of the brain kicks in. Every ancient instinct tells you to stay with your son or daughter, to protect them for as long as you possibly can. The only time I’d ever felt this way was when I went skydiving. When I peered out that door at 3,000 feet, my brain simply refused to let me jump. In the end, my jump instructor had to push me out the door. Decades later, standing in that dorm room at Shattuck-St. Mary’s, I felt the same way.

This time it was Jill who had to push me out the door. Like in that airplane, my feet just wouldn’t move. Later, at the airport terminal, we sat down for lunch, quietly contemplating what it would be like not seeing Tate every day. Not taking him to school in the morning. Not hearing him careen down the hallway with his hockey gear. Not being there when he had a rough game and needed a hug.

After we paid the bill, I walked to the gate while Jill lingered at the table to finish her glass of wine. I was walking by the Caribou Coffee shop when I noticed a young woman sitting alone at a table, sobbing. It was one of those intense cries when the world seems so very far away. I’ve been there many times, and I knew in my bones how that young woman was feeling.

At first, I kept walking. But when I reached my gate, I remembered the message of The Gift of Influence. When we walk on by, we miss opportunities to make a difference in the world. So, I turned around. Silently, I pulled up a chair at the woman’s table and said simply, “Rough day?”

She nodded, then said with a stuffy nose: “I just broke up with my boyfriend. I live in London, and he’s in Minneapolis. The long-distance was too much. I’m writing him a goodbye letter.”

As she said those words, I could tell she was barely keeping it together. Just like I’d been barely keeping it together back at Tate’s dorm a couple of hours earlier. Wordlessly, I gave the woman a hug. It was like a dam broke as we both started bawling. She told me how sad she was to say goodbye to the man she loved; I told her how sad I was saying goodbye to my son. We were from two different worlds, but in that moment, we understood each other. A minute later, Jill walked by and made eye contact with me. Yup, that’s my husband, she was thinking. Crying at the airport with a complete stranger.

Before I left, I told that woman that it would get better. I had been at that table many times before, and it always gets better. And then I left. I never got her name. I never got her contact information. We’ll almost certainly never meet again, and yet I know we’ll never forget that chance encounter.

My dear friend Matthew Kelly, the founder of Dynamic Catholic, calls opportunities like these “Holy Moments”—those small chances to collaborate with God to change the lives of others. No matter what you call them, they are choices. You can choose to change a life, or you can choose not to.

If you pay attention, you’ll notice opportunities every single day. It’s your colleague at work who’s having an awful day. The client who mentions they are going through a divorce. The employee who says their son or daughter is suffering from depression. Do you sit down with them and offer support—even if it’s a simple hug—or do you walk on by?

Here’s an example of someone who doesn’t walk on by. Because Tate will be in Minnesota for the next four years, Jill and I bought a townhouse near his school so we could visit him. So Tate will have a little place nearby he can call home. We bought the home from a realtor named Nancy Barr, who is now helping us remodel. We got talking one day, and I mentioned offhand that, like any fourteen-year-old away from home for the first time, Tate was feeling homesick. Now, most folks would say something like, “Aww, don’t worry, he’ll be fine.”

Not Nancy Barr. She took it upon herself to visit Tate every single day during his first week at school. She’s taken him to Subway. She’s taken him fishing. She attended his first game. She even cleaned his dirty laundry. If Tate needs anything at all—even if it’s just to hear a friendly voice—he knows he can call “Miss Nancy.”

A few days ago, I was talking to Tate on the phone when he said, “Dad, I think that Miss Nancy is Jesus.”

When I told Nancy this, she laughed and said, “No, I’m just Tate’s friend.”

Nancy Barr embodies everything I talk about in The Gift of Influence. She recognizes simple opportunities to positively impact another person. As for Tate, she didn’t change his life with some grand gesture. She isn’t Jesus—she simply did his laundry.

And most importantly, she didn’t walk on by.