Simon Sinek has spent the better part of his career teaching business leaders the importance of a single word: "Why."
As a leader, it's up to you to find and communicate your organization's Why — your greater purpose in the world. How are you changing people's lives with the product or service you offer?
If instead you get caught up in the trappings of wealth and fame, Sinek says you'll never truly be successful.
Sinek, who wrote the 2009 book "Start With Why," recently partnered with professional services firm EY in an initiative called "The Why Effect." The goal is to help organizations improve their performance by tapping into their greater purpose and putting people before numbers.
Finding your Why — and eschewing materialism — is certainly an inspiring idea. But we're all human beings, and it's only natural to want to be rich, famous, and powerful.
Sinek fully acknowledges this, and says there's one key way to prevent greediness from obscuring your sense of purpose: Find a leadership buddy.
"I always tell people, if you want to go on a leadership journey, you have to go with someone," Sinek told Business Insider. "You commit to helping somebody become a great leader, and they commit to helping you."
Sinek said your leadership buddy can be a colleague, but doesn't necessarily have to be. A friend or a mentor who aspires to leadership works just as well, as long as it's someone you believe in and you're willing to sacrifice your own interests to help. Maybe, for example, you spend your weekends working with them on a problem they're struggling with.
Sinek explained that leadership is a lot like parenting — your greatest happiness comes from seeing your child or your team do well and achieve more than you thought they were capable of. That in turn inspires you to go out and fulfill your own potential.
Sinek has multiple leadership buddies, he said. They talk on the phone regularly to share advice, stories, and new ideas, and stay humble by reminding each other that they're always learning.
"The best leaders are ones that don't consider themselves experts; they consider themselves students," Sinek said.
Ultimately, a leadership buddy will help you maintain your integrity as you move forward in your career because you'll constantly feel how fulfilling it is to serve other people.
"I find it ironic that if we go to the bookstore, there's a whole section called 'self help,'" Sinek said. "The thing that leads to the greatest joy is helping others."
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