I still regard adventure pretty much as a hobby to tell you the honest truth, and I think this approach to it keeps one refreshed almost. I think if you just regard adventure as a business, working becomes very boring as many other businesses can become. But even though adventure changed my life considerably, both in what I was doing and even economically, I’ve always regarded myself in a sense as a competent amateur.

It’s how we are made as homo sapiens. We are biologically organized to cover distances on foot. That’s what we did for tens of thousands of years until we started to use horses, of course, until the mechanical age. And I would not call it “walking” because it’s not going out for a stroll or going out for a “power walk” or ambling in your city. It’s “traveling on foot.” You are reading the world, learning the essence of the world.

It’s easy to try to exaggerate the problems just to get more attention. So for me, it was very clear that the best way to deal with that was to do the best science that I was capable of doing.

When you’re a carpenter making a beautiful chest of drawers, you’re not going to use a piece of plywood on the back, even though it faces the wall and nobody will ever see it. You’ll know it’s there, so you’re going to use a beautiful piece of wood on the back. For you to sleep well at night, the aesthetic, the quality, has to be carried all the way through.

The thing actually that I most dislike is cruelty. I can't stand cruel people. And if I see people doing something mean to somebody else, just to make themselves feel important it really gets me mad.

It's hard - truthfully the main thing other than work is just making sure that I'm spending enough time with michelle and the girls. The big advantage I have is that I live above the store - so I have no commute! So we make sure that when I'm in DC I never miss dinner with them at 6:30 pm - even if I have to go back down to the Oval for work later in the evening. I do work out every morning as well, and try to get a basketball or golf game in on the weekends just to get out of the bubble.

If you ask me where has been the one area where I feel that I've been most frustrated and most stymied it is the fact that the United States of America is the one advanced nation on earth in which we do not have sufficient common-sense, gun-safety laws. Even in the face of repeated mass killings. … And for us not to be able to resolve that issue has been something that is distressing. But it is not something that I intend to stop working on in the remaining 18 months.

And finally, change requires more than just speaking out -- it requires listening, as well. In particular, it requires listening to those with whom you disagree, and being prepared to compromise. When I was a state senator, I helped pass Illinois's first racial profiling law, and one of the first laws in the nation requiring the videotaping of confessions in capital cases. And we were successful because, early on, I engaged law enforcement.

One of the things that Michelle and I are proud of is that we came through the White House with our souls intact. Everybody has heard: Power corrupts. I do think if you are placed in such an artificial situation, and your office has great importance, there is a tendency for people to want to please you. To not be as honest with you. We fought against that.

And democracy requires compromise, even when you are 100 percent right. This is hard to explain sometimes. You can be completely right, and you still are going to have to engage folks who disagree with you. If you think that the only way forward is to be as uncompromising as possible, you will feel good about yourself, you will enjoy a certain moral purity, but you're not going to get what you want.