Facebook CEO Mark Zuckerberg shares 3 lessons of his life: believing in your mission, caring more deeply than anyone else and looking ahead.

Believe in your mission: Starting Facebook in 2004, Zuckerberg said he created the service because he wanted to solve a problem not because he wanted to build a business. At the time, there were ways to find books, movies and other material on the Internet but it was difficult to connect with people online. The social media site has gone through a flurry of changes since that time, including the creation of News Feed, a feature that some users did not like at first. Despite users who threatened to quit the service, Facebook didn't get rid of News Feed because the company knew it was a vital part of its mission. "We care about what people think. But we also know that connecting people is important. Most companies would be afraid of losing so many people, so they would take the easy path and give in," he said.

Care more deeply: Zuckerberg would spend nights at Harvard eating pizza and talking about the future with his classmates, but he didn't think at the time that he would be the one to build a service that connected the world. "I was just a college student. I thought a big company like Microsoft or Google would build this. They had thousands of engineers and hundreds of millions of users. They should have built the social network for the world. Why didn't they?," he said. The short answer, Zuckerberg said, is that they just cared more. There were doubts that Facebook could expand beyond college students, make money and even be used on mobile devices, but now the site has more than 1.5 billion users and is raking in billions of advertising dollars.

Look ahead: Despite Facebook's success, the social network's work to connect the world isn't done. The company launched Internet.org in 2013, an initiative to expand basic Internet service to developing countries. He told Facebook's board of directors then that he thought they should spend billions of dollars on this effort. "They asked me: how will this make money? I told them I don't know how. But I do know that connecting people is our mission and it is important. We must always look ahead and even if we don't know the whole plan now, if we help people, then in the future we will benefit too," he said.