Rationality is not just something you do so that you can make more money, it is a binding principle. Rationality is a really good idea. You must avoid the nonsense that is conventional in one's own time. It requires developing systems of thought that improve your batting average over time.
Charlie MungerAnother thing I think should be avoided is extremely intense ideology because it cabbages up one's mind. You see it a lot with T.V. preachers (many have minds made of cabbage) but it can also happen with political ideology. When you're young it's easy to drift into loyalties and when you announce that you're a loyal member and you start shouting the orthodox ideology out, what you're doing is pounding it in, pounding it in, and you're gradually ruining your mind. So you want to be very, very careful of this ideology. It's a big danger.
Charlie MungerLearn how to ignore the examples from others when they are wrong, because few skills are more worth having.
Charlie MungerI think the main figure that matters to all of us, including people in the media, is: How does GDP per capita grow? And those figures have been very good. There is a huge flux both up and down, so it isn't like we're all static in status. What's important is that pie grows.
Charlie Munger