We are very careful about what features we add because we can't take them away.

Be careful.

It takes these very simple-minded instructions - 'Go fetch a number, add it to this number, put the result there, perceive if it's greater than this other number' - but executes them at a rate of, let's say, 1,000,000 per second. At 1,000,000 per second, the results appear to be magic.

I do urge caution but do not be overly concerned if you see a mountain lion. You are pretty much safe everywhere. If you look at the risk factor you are more likely to be killed driving to a hiking trail than being attacked on a trail.

I have a great respect for incremental improvement, and I've done that sort of thing in my life, but I've always been attracted to the more revolutionary changes. I don't know why. Because they're harder. They're much more stressful emotionally. And you usually go through a period where everybody tells you that you've completely failed.

So they've got to be careful that they don't overdo it.