This week on our Vergecast interview series, The Verge’s editor-in-chief Nilay Patel chats with filmmaker Davis Guggenheim on his new documentary Inside Bill’s Brain: Decoding Bill Gates, which premiered on Netflix earlier this month.

Davis talks about the two years he spent filming with the Microsoft co-founder, as well as how he got Gates to participate in the film, the structure of the documentary, the most surprising things he learned about the man, and much more. Below is a lightly edited excerpt of the conversation.

Nilay Patel: I thought the most interesting part of the entire thing is when you were alone with him during his “Think Week” and he’s alone in the house and he’s reading books, and over time you see the Diet Coke cans pile up. I’ve never seen the richest man in the world open a can of Diet Coke. Most people don’t have that experience. It’s just very human and he’s literally alone. What was it like to go into that space with him?

Davis Guggenheim: Well, so interesting... I’ll pull the curtain a little bit when I’m making documentaries.

You say, okay, well here we are. We’re doing a time lapse of you working, right? And we’re going to start you reading at the late afternoon and then we’re going to have you reading and working till night so that we get a sense of time passing. I’ve done this in different projects. It’s often usually like the person says “What you want me to read?” or like “What page does it need to be on?” And for Bill it was just like “Oh, I get to read.”

I know the book, it’s Tara Westover’s book Educated, which he just picked up that day. It was on his list and he read for like an hour and 45 minutes. And we’re all moving around, moving lights, we’re moving camera positions, we’re all whispering, but I’m telling you... that guy just read as if we weren’t there, and drinking Diet Cokes at will.

So it’s kind of astounding his focus. Us having cameras and lights was really uninteresting to him. It was more like “Oh, I get a quiet moment to read? I’ll take my quiet moment to read.”

There’s many shots of him using a computer. Was it like “Bill, just use Excel for a while and we’re going to take some beautiful b-roll of you”? How would you set that up with Bill Gates?

In this case you just say, “Hey Bill, we want to film you at your desk working” and then he just does whatever he wants to do.

The one thing I did tell him to do — this is the end of the day and I knew he played online bridge — and so I was like, “Hey, why don’t you play online bridge now?”

He went and played online bridge for 45 minutes. But again, once I said to do it, he could care less that we were there. He was trying to win the bridge game.

What’s the thing that surprised you most about Gates?

He’s very emotional.

That actually is hugely surprising.

The first three or four interviews, I did not always see emotion. Melinda [Gates] talks about it. When they’re all watching a movie, the kids notice that he’s the first to cry. He cries a lot and I think he presents... because his intellect is so powerful and he believes so much in sort of rational thinking and optimization of things, that he always leads with that.

This is me speaking for what I think he thinks, which is I think he truly believes that emotions shouldn’t cloud your decisions. And too often businesses and nonprofits and foundations, their decision-making is clouded by emotion. Certainly, it happens to me all the time. He wants to be analytical. He doesn’t share that side of him. And that’s a shame. And I think the series starts to reveal that about him. I think you see someone who is very driven by wanting to do good in the world. Driven by a sense of deep, deep unfairness that children on the other side of the world are dying for things that his children have.

There’s a scene where he’s going through the stats of how many kids have polio and how many people he can save. And you say something like “Well, that’s not very inspiring.” He’s like “Yeah, so what?” And it occurs to me that he’s the person who needs to be inspired, like he’s got the money and the power. He’s got to get affected. And it sounds like you’re saying he is actually deeply affected.

He is deeply affected or else why wouldn’t he just be like buying art or, you know, huge toys like other billionaires do? I mean, I actually don’t know why he doesn’t. I’m only guessing why he doesn’t display his emotion more. You know, people think of him as sort of like an analytical guy who doesn’t have emotions. I think he’s deeply emotional. He just doesn’t show it.

Inside Bill’s Brain: Decoding Bill Gates is now available on Netflix.