John Templeton
"The four most dangerous words in investing are 'This time its different.'"

Jesse Livermore
"The market does not beat them. They beat themselves, because though they have brains they cannot sit tight."

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."