"You are lucky in life. And you are lucky in war," Guggenheim says, referring to the card game.
"And love, too," says Gates.
In the documentary, which was released Friday, the 63-year old centibillionaire is obviously grateful for his wife, Melinda. But perhaps that wasn't always so clear.
Bill met Melinda shortly after she joined Microsoft as a product manager in 1987, when they sat next to each other at a business dinner in New York City. After about a year of dating, they came to a crossroads. "You know, we cared a lot for each other and there were only two possibilities: either, we were going to break up or we were going to get married," Bill says.
"He had to make a decision," Melinda says in the documentary series. One day Melinda walked into Bill's bedroom and he was making a list on a whiteboard: "his whiteboard had the pros and the cons of getting married," Melinda says in the series, bursting into laughter at the memory.
It may not be the most romantic thing, but Bill's whiteboard list was reflective of the weight of the decision: "I took the idea of marriage very seriously," Bill says.
Bill's own parents — Bill Gates Sr., an attorney, and Mary Maxwell Gates, a Seattle business woman — were equal partners both in their professional aspirations and their play, Melinda observes.
Bill wasn't sure he was ready to make that kind of commitment because he "wanted to be married, but he didn't know whether he could actually commit to it and [run] Microsoft," Melinda says.
Originally, when Bill and Melinda started dating, the relationship was casual for both of them.
"She had other boyfriends, and I had Microsoft," Bill says. "We were like, 'Hey we are not really serious about each other, are we? We are not going to demand each other's time.'"
Plus, Melinda says, "I was new to Microsoft, there were a lot of men there and ... you are still looking around."
But after about a year, "sort of to our surprise, certainly my surprise, we said, 'Hey, I love you.'" Bill said. "And she said she loved me and then it was like, 'Wow, and now what is going to happen?'"
What happened was Bill asked Melinda to marry him, and in 1994 they tied the knot in Lanai, Hawaii. At the time, Gates was 38 and Melinda was 29, according to the Associated Press.
Today, the husband-and-wife duo co-run the Bill & Melinda Gates Foundation, which works on global health and development issues like eradicating polio, improving sanitation systems in impoverished countries and developing clean, affordable energy.
"In the case of Melinda, it is a truly equal partner," Bill says in the documentary. "She's a lot like me in that she is optimistic and she is interested in science. She is better with people than I am. She's a tiny bit less hard core about knowing, you know, immunology, than I am."
And while it's funny to imagine Bill listing the pros and cons of getting married on a whiteboard, it is after all, a big decision. Bill's billionaire buddy Warren Buffett says it's one of the most crucial decisions a person can make.
"You will move in the direction of the people that you associate with. So it's important to associate with people that are better than yourself," Buffett said in a 2017 conversation with Gates at Columbia University.
"And the most important person by far in that respect is your spouse," Buffett said. "I can't overemphasize how important that is."
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