What I’ve got doesn’t hurt. I’ve been lucky. The treatment has been benign. I don’t know if I could concentrate if I was in pain. I’ve never had to stop.

The second filter is to gravitate towards working on hard things. I’d love to tell you I was an immediate success after leaving Stanford… I wasn’t. Even a decade later, I felt like I wasn’t on the right path, and it took me a while to find my footing. Until I applied to Google. I had my final interview there in 2004, it was April Fool’s Day and the day Gmail launched. So when my interviewers asked me about it, I wasn’t sure if it was a joke or a real product. That’s because at the time, one gigabyte of free storage for everyone felt super ambitious, and almost impossible. A couple years into the job, I got my chance to work on a seemingly impossible problem, too. It was around this time that the internet was moving into a new phase. The web was evolving from simple web pages to rich applications. There was a group of us that felt we could reimagine the browser to be much better and faster, and we had an early prototype that we thought was pretty good. Internally there was a consensus that building a browser would be incredibly difficult, requiring hundreds of engineers; we had a group of about ten. The consensus was right. It was going to be really hard. In some ways we were naive, and it's good to be a bit irrational when you approach new things. And in 2008, we launched what we thought was a great browser. We had eight million users in the first twenty-four hours, and the reviews were really positive. And then user growth stagnated. After a year, we had around two percent share. I remember Steve Ballmer, the CEO of Microsoft, made fun of Chrome in an interview and called it a rounding error. It could have been demoralizing. But with that California optimism, I told the team that the fact he went out of his way to dismiss us meant we were doing something right. We kept going, setting highly aggressive stretch goals to keep the team pushing. We rapidly iterated, shipping the browser every six weeks while others shipped one maybe every six months to a year. Success began to follow. Working on hard things has taught me a lot: It typically attracts other great and optimistic people. And even if you miss meeting the high goals you set, you’ll still achieve something great. So when you have the choice to work on something hard — say yes. Do what excites you

The hard part was getting around this, this was a religion among physicists, and in fact even in the Bohr-Einstein debates, and with Schrödinger also, the universal religion was quantum mechanics makes correct predictions, period, no, off the table. What Bell's theorem and in particular our version of it, the Clauser-Horne-Shimony-Holt experimental prediction, showed that either that had to be wrong, nor Einstein's whole legacy had to be wrong. I think at the time people who were critical of doing the experiment didn't realise really what was at stake, that it was that cut and dried between two religious icons, if you will, the field of physics. Since I kind of was the inventor of the CHSH inequality and the CH inequality and all that, I knew exactly what it was all about. But it took a long time for that to filter in.

Then you have the clients. The care and feeding of clients is really one of the main obstacles, because you always have a client with some preconceived idea of what a house looks like, and all you want him to do is leave a check and go to Europe for a couple of years. Or leave two checks. But alas, life isn’t simple. If it were, more people would be better architects.

I've had some downturns in my career and various problems, but in fact all those kind of problems turned into something even better. It's kind of amazing, various times in my career.