Why are some companies more innovative, more profitable, and inspire greater loyalty from customers and employees alike? It’s because they start by asking “why,” according to Simon Sinek, an ethnographer, author of Start With Why: How Great Leaders Inspire Everyone to Take Action and speaker (his TED speech is among my favorites).

“People don’t buy what you do, they buy why you do it,” says Sinek. Your story and your passion make you stand out in a crowd and help you connect with like-minded people, the kind of people who will support you even when times are tough.

When you follow your heart and are passionate about what you do, you lay the foundation for creativity. That keeps you motivated. When obstacles get in your way, you have the strength to go on. Over the past few months, I’ve had the pleasure of interviewing four start-up entrepreneurs whose passion and purpose inspire me, their customers, employees, suppliers, and investors.