The harder you work, the more confidence you get. But you may be working hard on something that is false.

What matters most: passion or competence that was born in? Berkshireis full of people who have a peculiar passion for their own business. I would argue passion is more important than brain power.

Beta and modern portfolio theory and the like - none of it makes any sense to me.

Size will hurt returns. Look at Berkshire Hathaway - the last five things Warren has done have generated returns that are splendid by historical standards, but now give him $100 billion in assets and measure outcomes across all of it, it doesn't look so good. We can only buy big positions, and the only time we can get big positions is during a horrible period of decline or stasis. That really doesn't happen very often.

I have what I call an iron prescription that helps me keep sane when I naturally drift toward preferring one ideology over another and that is: I say that I'm not entitled to have an opinion on this subject unless I can state the arguments against my position better than the people who support it. I think only when I've reached that state am I qualified to speak. This business of not drifting into extreme ideology is a very, very important thing in life

The cost of being a publicly traded stock has gone way, way up. It doesn't make sense for a little company to be public anymore. A lot of little companies are going private to be rid of these burdensome requirements.

People calculate too much and think too little.