Whenever there is hard work to be done, I assign it to the laziest man as he is sure to find an easy way of doing it. Be lazy, think crazy.

Success is a lousy teacher. It makes you think you know what you're doing.

The 'Billionaire' song is what my kids tease me with. They sing it to me. It's funny.

Imagine, just for the sake of discussion, that you had a few hours a week and a few dollars a month to donate to a cause - and you wanted to spend that time and money where it would have the greatest impact in saving and improving lives. Where would you spend it?

Some very poor countries run great vaccination systems, and some richer ones run terrible programs.

My mom was on the United Way group that decides how to allocate the money and looks at all the different charities and makes the very hard decisions about where that pool of funds is going to go.

We weren't trying to just go public and get rich. There was no near-term thing. It always was this many-decades thing where there were no shortcuts and we'd sort of put one foot in front of the other.