The hedge fund known as "Long Term Capital Management" collapsed last fall through overconfidence in its highly leveraged methods, despite I.Q.'s of its principals that must have averaged 160. Smart people aren't exempt from professional disasters from overconfidence. Often, they just run aground in the more difficult voyages they choose, relying on their self-appraisals that they have superior talents and methods.

An investment decision in the common stock of a company frequently involves a whole lot of factors interacting ... the one thing that causes the most trouble is when you combine a bunch of these together, you get this lollapalooza effect.

Like the stocks of both Berkshire and Wesco to trade within hailing distance of what we think of as intrinsic value. When it runs up, we try to talk it down. That's not at all common in Corporate America, but that's the way we act.

Great investing requires a lot of delayed gratification.

The beauty of a financial institution is that there are a lot of ways to go to hell in a bucket. You can push credit too far, do a dumb acquisition, leverage yourself excessively - it's not just derivatives [that can bring about your downfall].

If you skillfully follow the multidisciplinary path, you will never wish to come back. It would be like cutting off your hands.

A banker who is allowed to borrow money at X and loan it out at X plus Y will just go crazy and do too much of it if the civilization doesn't have rules that prevent it.