What's your favorite part of a typical day?

Anytime I'm building something new.

What's the least glamorous thing you do in the line of duty?

Going through airport security.

What skill would you most like to improve?

Humor. I've been researching the science of humor, and I think it can be learned like any skill.

What's the simplest thing you never learned to do?

To whistle.

What accomplishment are you most proud of?

Being involved in building the Zappos culture.

What keeps you up at night?

Trying to figure out how to make the company culture stronger as we get bigger.

Who is the smartest person you know?

I believe that people are smart in different ways. With everyone I meet, I try to figure out what they're smart about and learn from them.

If you could go back and do one thing differently, what would it be?

I would try to do everything faster.

What was the happiest day of your career?

Our company milestones -- like when we signed Nike after trying to get them for eight years.

On a scale from 1 to 10, how happy are you right now?