“Do you really believe that a person can make a living doing anything they love to do?”

I looked right into the earnest, dubious face across from me and gave an honest answer, “Yes, I do.”

Of course, we’d love to believe that it’s that easy, or at least that simple. “Do what you love, the money will follow” has been a bone of contention since the book of the same name came out. If you read that book you know that even the author didn’t pretend it was simply a matter of loving to doodle and getting paid enormous sums for doodling. There is another simple principle behind my confidence that yes, you can make a living doing anything. Whether you love it or not, but if you don’t love it what’s the point?

Here is that principle: you are paid for the impact you have in the world.

If you can do what you love in a way that inspires, entertains, educates, illuminates, improves lives or otherwise impacts one or more people, and you put the foundation of a good business model with that activity, you can get paid. If you can impact enough people, or impact one person deeply enough, and have a really solid business model you can get paid a lot.

Which means you have to pay attention to people. Not trends, people.

Related: 5 Essential Ingredients to Doing What You Love For a Living

When Gary Dahl launched a company selling rocks, Pet Rocks, he wasn’t riding a trend. He was betting that people would buy something that amused and entertained them. He didn’t really think people wanted rocks from Mexico, but he believed that people would spend money to get a “pet” and read the witty 32-page training manual or have fun gifting the rocks in their special “pet carrier.”

Dahl won that bet. In the six months that Pet Rocks were a fad Gary became a millionaire. He impacted a lot of lives in a small way, and made a living doing it.

I don’t know if Gary Dahl loved Pet Rocks. He was an advertising guy, so if I had to make a guess at what he loved it would be that he loved being clever and providing amusement while selling something that was only valuable because of its entertainment value.

What do you love? Quite often it isn’t the “pet rock” you’re selling or the activity you’re doing, it’s something deeper than that. How will you discover a way to make a living doing what you love if you haven’t examined what that really is?

Related: How to Find Your Passion in 5 Creativity Exercises

Or maybe you know what you love. But you haven’t figured out how it impacts the lives of others. Maybe you love to create art -- painting, writing, music, or chalk drawings. In the co-working space where we have an office there is one huge wall painted with chalk paint and updated periodically with intricate chalk art. The company, Chalk Riot, also has an office here but their work shows up all over St. Louis and beyond. The founders knew what they loved to do, and they saw a way to impact lives by doing it. Art is a beautiful personal thing, but if it doesn’t impact someone else no one will pay you to provide it.

The key to going from love to living is focus on people.

Too many entrepreneurs spend their time and energy focused on what they love and trying to convince other people to love it too. Those entrepreneurs who focus on people -- learning their desires, fears, habits and beliefs, learning how they think and what they respond to -- also learn how they can impact people by doing what they love. Those are the entrepreneurs who make a living, and a lifestyle, out of doing it.

Related: 7 Tips for Loving Your Career and Working With Passion