So it's not surprising the business titans agree that who you spend time with matters.
By choosing the right group of friends, you can push yourself to achieve bigger professional goals, Buffett and Gates say.
"You will move in the direction of the people that you associate with," says Buffett, who recently addressed a group of students at Columbia University along with Gates.
"It's important to associate with people that are better than yourself."
Gates says your social circle is an important investment of time and energy.
"Some friends do bring out the best in you," the Microsoft co-founder says, "and so it's good to invest in those friendships."