Microsoft is always two years away from failure.

There's only one trick in software, and that is using a piece of software that's already been written.

In low-income countries, the main problems you have is infectious diseases.

If you can't make it good, at least make it look good.

Teaching's hard! You need different skills: positive reinforcement, keeping students from getting bored, commanding their attention in a certain way.

It is a high bar to say that it's more fun than working on software because the work at Microsoft that both Melinda [Gates] and I did was thrilling. We were making breakthroughs and empowering people.

If you're too focused on your current business, it's hard to change and concentrate on innovating.