Made me think (as most of the lessons coincide) about the book I'm reading at the moment - 'Money: Master the Game' by Tony Robbins: http://moneymasterthegame.com/
He says he believes the market may be entering a dangerous period and all but advises getting out of stocks. (Watch part 1 and part 2). If you followed his advice from 2010 until now, you've lost out big time. My point isn't that Tony Robbins was wrong, it's that it is very hard to predict the market.