It's not going to do any good to land on Mars if we're stupid.

And it is easy to believe you are not good enough if you listen to everybody else.

No matter how full a reservoir of maxims one may possess, and no matter how good one's sentiments may be, if one has not taken advantage of every concrete opportunity to act, one's character may remain entirely unaffected for the better.

Those who forget good and evil and seek only to know the facts are more likely to achieve good than those who view the world through the distorting medium of their own desires.

My best moment? I have a lot of good moments but the one I prefer is when I kicked the hooligan.