Investing is not nearly as difficult as it looks. Successful investing involves doing a few things right and avoiding serious mistakes.
John C. BogleIt's very difficult for any particular segment of the stock market to sustain superior performance. The watch word for our financial markets is, "reversion to the mean" i.e. what goes up must come down, and it's true more often than you can imagine.
John C. BogleBut whatever the consensus on the EMH, I know of no serious academic, professional money manager, trained security analyst, or intelligent individual investor who would disagree with the thrust of EMH: The stock market itself is a demanding taskmaster. It sets a high hurdle that few investors can leap.
John C. Bogle