The key to investing is not assessing how much an industry is going to affect society, or how much it will grow, but rather determining the competitive advantage of any given company and, above all, the durability of that advantage.
Accounting consequences do not influence our operating or capital-allocation decisions. When acquisition costs are similar, we much prefer to purchase $2 of earnings that is not reportable by us under standard accounting principles than to purchase $1 of earnings that is reportable.
If you expect to continue to purchase stocks throughout your life, you should welcome price declines as a way to add stocks more cheaply to your portfolio.
A prediction about the direction of the stock market tells you nothing about where stocks are headed, but a whole lot about the person doing the predicting.
If you own a wonderful business...the best thing to do is keep it. All you're going to do is trade your wonderful business for a whole bunch of cash, which isn't as good as the business, and you got the problem of investing in other businesses, and you probably paid a tax in between. So my advice to anybody who owns a wonderful business is keep it.