If you’re into leadership trainings, you’ve likely heard of Simon Sinek and his “Start with Why” idea — which is also the title of one of his books and his TED Talk.

The idea — in a nutshell — is that people don’t buy a product, service, movement or idea until they understand the “why” behind it. He illustrates the idea with what he calls the “Golden Circle.” In the outer most part of the circle is the what. Businesses and people know what they do. The next ring in on the circle is the how. Most companies know how they do what they do.

Fewer companies and people, though, know why they do what they do, and even fewer can communicate that “why” effectively. That’s what sets great people, ideas and companies apart.

An example he often uses is Apple. Apple, he says, believes in challenging the status quo and thinking differently. The way they do that is by making beautifully designed products that are user friendly. They happen to make great computers. But the reason we’re comfortable buying music players, DVRs, phones and other products from Apple is because we believe in why they do what they do, not just what they do, Sinek says.

Whether you buy into his Apple example, it’s easier to connect with a product if you believe in the “why” behind it.

This idea resurfaced recently after I had lunch with a friend who is trying to tackle this big beautiful project. She talked for a couple hours about what she and her organization are trying to accomplish. It’s not a small task — in fact it includes a complete transformation of how we view each other.

She told me a story — a very personal story — about why she has taken on the work she has. She isn’t sure how she will make it sustainable and she’s unsure of whether she’s worthy of taking on the challenge, but she sure knew her “why.”

That’s all I needed to know.

This person has talked to me a lot about what she is doing over the last couple of years, but until this lunch, she hadn’t voiced the why. Now, I’m hooked. I want to dedicate time, energy, social capital and knowledge to helping her achieve this big shift in perception and how we interact with people. I bought her why.

So if you’re struggling to find support for a project — whether it’s for a business, nonprofit or personal — Simon says, “start with why.”