Jesse Livermore
"A great many smashes by brilliant men can be traced to the swelled head - an expensive disease everywhere to everybody, buy particularly in Wall Street to a speculator."

Warren Buffett
"The most common cause of low prices is pessimism - some times pervasive, some times specific to a company or industry. We want to do business in such an environment, not because we like pessimism but because we like the prices it produces. It's optimism that is the enemy of the rational buyer."

Warren Buffett
"In my early days as a manager, I, too dated a few toads. They were cheap dates - I've never been much of a sport - but my results matched those of acquirers who courted higher-priced toads. I kissed and they croaked." [On acquiring bad companies for cheap prices]