We all are learning, modifying, or destroying ideas all the time. Rapid destruction of your ideas when the time is right is one of the most valuable qualities you can acquire. You must force yourself to consider arguments on the other side.
Charlie MungerWe believe that almost all really good investment records will involve relatively little diversification. The basic idea that it was hard to find good investments and that you wanted to be in good investments, and therefore, you'd just find a few of them that you knew a lot about and concentrate on those seemed to me such an obviously good idea. And indeed, it's proven to be an obviously good idea. Yet 98% of the investing world doesn't follow it. That's been good for us.
Charlie MungerWe bought a doomed textile mill [Berkshire Hathaway] and a California S&L [Savings & Loan; Wesco] just before a calamity. Both were bought at a discount to liquidation value.
Charlie Munger