“There are no checks on the swings of investor psychology. At times investors get crazily bullish and can imagine no limits on prosperity, growth and appreciation. They assume trees will grow to the sky. Nothing’s too good to be true. And on other occasions, correspondingly, despondent investors can’t think of any limits to how bad things can get. People conclude that the “worst case” scenario they prepared for isn’t negative enough. Highly disastrous outcomes are considered plausible, even likely. Over the years, I’ve become convinced that fluctuations in investor attitudes toward risk contribute more to major market movements than anything else. I don’t expect this to ever change.” —Howard Marks