Focusing is about saying No.

My philosophy is that everything starts with a great product.

When you're doing something for yourself, or your best friend or family, you're not going to cheese out. If you don't love something, you're not going to go the extra mile, work the extra weekend, challenge the status quo as much.

When you're in a start-up, the first ten people will determine whether the company succeeds or not. Each is 10 percent of the company. So why wouldn't you take as much time as necessary to find all the A players? If three were not so great, why would you want a company where 30 percent of your people are not so great? A small company depends on great people much more than a big company does.

Design is not just what it looks like and feels like. Design is how it works.

When you grow up, you tend to get told that the world is the way it is, and your life is just to live your life inside the world. Try not to bash into the walls too much. Try to have a nice family life. Have fun, save a little money. That's a very limited life. Life can be much broader, once you discover one simple fact, and that is everything around that you call life was made up by people who were no smarter than you. And you can change it. You can influence it. You can build your own things that other people can use. Once you learn that, you'll never be the same again.

Design isn't just how it looks. It's how it works.