In Gillette's case, they keep surfing along new technology which is fairly simple by the standards of microchips. But it's hard for competitors to do. So they've been able to stay constantly near the edge of improvements in shaving.

The number one idea is to view a stock as an ownership of the business and to judge the staying quality of the business in terms of its competitive advantage. Look for more value in terms of discounted future cash-flow than you are paying for. Move only when you have an advantage.

Projections are put together by people who have an interest in a particular outcome, have a subconscious bias, and its apparent precision makes it fallacious. They remind me of Mark Twain's saying, 'A mine is a hole in the ground owned by a liar.' Projections in America are often a lie, although not an intentional one, but the worst kind because the forecaster often believes them himself.

When you mix raisins and turds, you've still got turds.

Don't confuse correlation and causation. Almost all great records eventually dwindle.

I think the idea that the hedge fund manager gets lower taxes than the taxi driver or the physics professor is insane. The legislators who leave that policy in place are derelict in their duties to be rational and fair. There are plenty of them in both political parties. It's totally outrageous.

Warren is one of the best learning machines on this earth. The turtles who outrun the hares are learning machines. If you stop learning in this world, the world rushes right by you.