Even the most successful people don't have all the answers.
"When I was going through [the question of] what should we do on returning cash to shareholders, I thought who could really give us great advice here? Who wouldn't have a bias?" he told McGregor. "So I called up Warren Buffett. I thought he's the natural person."
On a separate occasion, when Cook testified before Congress for the first time in a hearing about Apple's tax practices, he turned to Goldman Sachs CEO Lloyd Blankfein and former President Bill Clinton.
"I've never testified in front of Congress before," Cook said. "I looked back to say who's done this before? I knew Lloyd and thought he'd be honest with me. I called up President Clinton. He knows a lot about the politics."
Just because you ask for advice doesn't mean you have to take it, but it's important to actively seek out other perspectives, Cook said: "I think it's incumbent on a CEO to not just listen to points of view but to actually solicit them. Because I think, if not, you quickly become insular. And you're sort of living in the echo chamber."
After all, there's a reason successful people typically create what steel tycoon Andrew Carnegie called "Master Mind" groups, meaning they surround themselves with other talented and highly successful people.
As journalist Napoleon Hill, who studied over 500 self-made millionaires, explained in his 1939 classic, "Think and Grow Rich," the alignment of several smart and creative minds is exponentially more powerful than just one.
"A group of brains coordinated (or connected) in a spirit of harmony will provide more thought-energy than a single brain," Hill wrote. "Analyze the record of any man who has accumulated a great fortune, and many of those who have accumulated modest fortunes, and you will find that they have either consciously, or unconsciously employed the 'Master Mind' principle."