I don't enjoy it but I know that I have got to live with [myself] if I'm not going to give it 100 per cent. The key thing is getting to the start line and knowing that I couldn't have done any more, that I didn't back off. You accept the pain, because if you didn't there would always be that element of doubt.

There were times when I thought I wanted to be a cartoonist. If I weren’t a film director, I think cartoons would have been a good alternative. But I never properly studied drawing, so my drawings are strange. But when I’m prepping films, it’s good preparation — and comforting to me — to do the storyboards. It’s fun, too, like drawing a whole comic.

you have got to be totally honest and give advice and analysis that you’re asked to give that’s based on evidence. And if the analysis that you come to comes to a conclusion that a president might not like to hear that, you can’t be afraid of saying, “Mr. President, with all due respect, this is the way I think the situation is.”

I notice that if you have the door to your office closed, you get more work done today and tomorrow, and you are more productive than most. But 10 years later somehow you don't know quite know what problems are worth working on; all the hard work you do is sort of tangential in importance. He who works with the door open gets all kinds of interruptions, but he also occasionally gets clues as to what the world is and what might be important.

I've actually felt slightly uncomfortable at TED for the last two days, because there's a lot of vision going on, right? And I am not a visionary. I do not have a five-year plan. I'm an engineer. And I think it's really — I mean — I'm perfectly happy with all the people who are walking around and just staring at the clouds and looking at the stars and saying, “I want to go there.” But I'm looking at the ground, and I want to fix the pothole that's right in front of me before I fall in.

I mean, I still work alone. Really — I work alone in my house, often in my bathrobe. When a photographer shows up, I dress up, so I have clothes on. And that's how I've always worked.