Optimists are usually wrong. But all the great change in history, positive change, was done by optimists.

Rock stars get room keys, I get business cards. Wherever I go I meet innovators of wind power equipment, solar energy operators.

There's no question that a great teacher can make a huge difference in a student's achievement, and we need to recruit, train and reward more such teachers. But here's what some new studies are also showing: We need better parents. Parents more focused on their children's education can also make a huge difference in a student's achievement.

The country that owns green, that dominates that industry, is going to have the most energy security, national security, economic security, competitive companies, healthy population and, most of all, global respect.

America still has the right stuff to thrive. We still have the most creative, diverse, innovative culture and open society - in a world where the ability to imagine and generate new ideas with speed and to implement them through global collaboration is the most important competitive advantage.

We need better neighbors, neighbors that care about the schools in their neighborhood whether they have kids in them or not, because they know that the health and vitality of that neighborhood depends on it.

It created a global platform that allowed more people to plug and play, collaborate and compete, share knowledge and share work, than anything we have ever seen in the history of the world.

We are led by lawyers who do not understand either technology or balance sheets.

There is nothing more valuable than great classroom instruction. But let's stop putting the whole burden on teachers. We also need better parents. Better parents can make every teacher more effective.

Nature is regulating our climate for free. Mother Nature, she's been doing that for free, for a long, long time. Now do you really want to get in there and do geo-engineering and all this kind of stuff?

I said that more people in more places can now compete, connect and collaborate with equal power and equal tools than ever before.

By 'flat' I did not mean that the world is getting equal. I said that more people in more places can now compete, connect and collaborate with equal power and equal tools than ever before. That's why an Indian in Bangalore can take care of the office work of American doctors or read the X-rays of German hospitals.

Golf has an ambivalent relationship with the environment. On one hand, it's a great preserver of open spaces. Golf doesn't pave the world - it helps to green the world. But the downside is, it uses a lot of fertilizer, pesticides and water.