Find that thing you are super passionate about. A lot of founding principles of Facebook are that if people have access to more information and are more connected, it will make the world better; people will have more understanding, more empathy. That’s the guiding principle for me. On hard days, I really just step back, and that’s the thing that keeps me going.

Just because you can build a machine that is better than a person at something doesn't mean that it is going to have the ability to learn new domains or connect different types of information or context to do superhuman things. This is critically important to appreciate.

If you don't risk anything you risk everything

Think about what people are doing on Facebook today. They're keeping up with their friends and family, but they're also building an image and identity for themselves, which in a sense is their brand. They're connecting with the audience that they want to connect to. It's almost a disadvantage if you're not on it now.

Facebook was not originally created to be a company. It was built to accomplish a social mission - to make the world more open and connected.

When I look around the world and see so many countries turning people away, I think it is terrible. And I know that these are all issues that Germany is culturally dealing with in terms of integration but it is just something that I deeply admire.

The trick isn't adding stuff, it's taking away.