"We both certainly share a curiosity about the world," says Buffett, speaking at a Facebook live event broadcast from Columbia University and moderated by Charlie Rose.
The two first met in 1991 at a dinner that, Buffett jokes, Gates' mother had to convince him to attend. At the meal that would launch a long and enduring friendship, Gates' dad asked the two men what they felt their most important quality was.
They each had the same answer: curiosity.
Their friendship was almost instant, largely driven by the shared desire to learn more about their environment.
"We find the world just such an interesting place, so we like to compare notes," says Buffett, who founded Berkshire Hathaway and has an estimated net worth of $73 billion.