What it's like to work with a billionaire, according to ex-colleagues of Elon Musk, Jeff Bezos, Bill Gates, and Sara Blakely

• The lives and working routines of billionaires fascinate those who want to understand their success.
• Past colleagues discussed working with Bill Gates, Elon Musk, Jeff Bezos, and Sara Blakely.

The lives and working routines of billionaires fascinate those hungry to understand their success. Their eccentricities and rules for life are the subject of books, podcasts, and countless articles.

Their close colleagues know these captivating figures well. Here, people who've worked alongside Elon Musk, Jeff Bezos, Bill Gates, and Sara Blakely talk about what it was like.

Bill Gates could tell when someone had 'slung the bull'

Chris Williams will never forget the "grilling" he says the billionaire Microsoft cofounder Gates gave him when they first met in 1992.

After buying their company, Gates interrogated Williams and his colleagues about why their product was better than its Microsoft rival's. In eight years of meeting regularly one-on-one with Gates as a Microsoft executive, Williams learned how Gates' questioning was a way of exposing who "slung the bull." He'd keep pressing until the person under questioning would either admit they didn't know or start inventing things.

"It was hard to be in those rooms many times and not pick up some of that skill," Williams wrote for Insider, adding: "In time I could recognize the face of someone who, it seemed, would rather die than say, 'I don't know, but I'll find out and get back to you.'"

Williams also recalled Gates' ability to absorb "miles of data and dozens of opinions on the correct path" at a meeting and immediately identify what mattered and what to do.

Read more: I worked closely with Bill Gates for 8 years as an executive at Microsoft. Here are the 3 lessons he taught me that I'll never forget.

Jeff Bezos insisted on a 'deliberately inefficient' meeting

Colin Bryar, a former Amazon vice president and chief of staff to Bezos, listed 13 insights he gained in the 12 years of working closely with him.

These included the importance of reacting quickly to trends, doubling down on initiatives that bear fruit to minimize risk, and accepting that "getting a team on the same page is a lot of work."

On the last point, Bryar described how Bezos would hold a weekly four-hour meeting with his direct reports instead of one-to-one meetings with each of them. They would all attend regardless of whether the agenda touched on their responsibilities. Bezos wanted them to learn one another's responsibilities to help them work together as a team "when the inevitable crisis would arise," Bryar wrote.

He added, "I've seen many dysfunctional executive teams that just are not used to working together and something like a deliberately inefficient weekly meeting getting them together would help."

Read more: I'm a former Amazon VP who was there for 12 years and also served as Jeff Bezos' chief of staff. Here are the top insights I learned from him that have helped me in my career.

'Girl next door' Sara Blakely was a 'creative genius'

Lisa Magazine and Kenya Graham were personal and executive assistants, respectively, to Blakely, the Spanx founder. Magazine described Blakely as "the girl next door" but also "one of the most creative geniuses I've ever met." She told the podcast "Reach" that she was the 13th Spanx employee, joining when it was working out of a windowless basement in an Atlanta hotel.

She and Graham would plan Blakely's day, covering every aspect of her life to make Blakely "feel like a million dollars" whenever she stepped into a meeting. "There were so many times that Lisa and I would go over to the home, print out Sara's calendar, and sit with her husband's assistants and the house staff," Graham said. The pair often also collaborated on calendars and cc'd each other on emails and texts to ensure they were on the same page.

After Blakely gave the keynote at the Nordic Business Forum in 2019, the organizers told her that their team was the most prepared group they'd ever worked with, Magazine said.

Read more: Billionaire Sara Blakely's 2 assistants explain what it takes to keep her life running smoothly — and how there's no room for egos

Elon Musk could be 'fun' — but was also quick to fire people

During his early days at Tesla, Carl Medlock was in a meeting in which someone disagreed with Musk. Medlock, then a territory manager at Tesla, says he never saw the employee again. Musk is "not one for people back talking — he'll just let you go," Medlock told the podcast "The Iced Coffee Hour."

"When Elon stands up at the end of a meeting and says, 'This is the direction we're going to go,' you stand up from your chair, and you better head that direction," Medlock continued.

He said that despite this, however, Musk could be "fun" if you were on his good side and "for a guy who wasn't from the car industry, he asked some very good questions" of Medlock during his final interview for the role.

Medlock said he never saw his boss socialize or joke around with employees.

"He'd talk to you if he needed to talk to you, but he didn't just go BS with people at all," Medlock said. Even in meetings, he added, Musk didn't waste time chatting and got straight to the point.

Read more: Elon Musk was a 'fun' boss but fired people on the spot if they disagreed with him, former Tesla manager says