Laszlo Bock: "Without humility, you are unable to learn. Successful bright people rarely experience failure, and so they don't learn how to learn from that failure."
"What we've seen is that the people who are most successful here will have a fierce position. They'll argue like hell. But then you say 'Here's a new fact,' and they'll go 'Oh, that changes things; you're right.'"
"You need a big ego and small ego in the same person at the same time."
This is why Google asks behavioral questions about times you changed your mind or admitted a mistake. They want people who can update their beliefs when presented with new evidence.