“What I've learned over the years is that focus and singular purpose is the best approach for businesses.”

Cinema.com interview (2001)
Context: The most important lesson I've learned in this business is how to say no. I have said no to a lot of temptations, and I am glad I did.

Source: The Brass Verdict

He's got the whole world in his hands, The Telegraph (24 March 2007)

1989 Chairman's Letter http://www.berkshirehathaway.com/letters/1989.html
Letters to Shareholders (1957 - 2012)
Context: After 25 years of buying and supervising a great variety of businesses, Charlie and I have not learned how to solve difficult business problems. What we have learned is to avoid them. To the extent we have been successful, it is because we concentrated on identifying one-foot hurdles that we could step over because we acquired any ability to clear seven-footers.

Source: The impossible dream https://www.victoriaadvocate.com/news/business/the-impossible-dream/article_9f89419a-976d-520e-a2bc-844d245bbdc2.html (June 27, 2015)

Campaign rally, Madison, Wisconsin, CSPAN: Campaign 2008 (18 February 2008)
2000s
Context: What we've learned over this year is that hope is making a comeback. It is making a comeback. And let me tell you something — for the first time in my adult lifetime, I'm really proud of my country. And not just because Barack has done well, but because I think people are hungry for change. And I have been desperate to see our country moving in that direction and just not feeling so alone in my frustration and disappointment. I've seen people who are hungry to be unified around some basic common issues, and it's made me proud.