Investing is the greatest business in the world because you never have to swing. You stand at the plate; the pitcher throws you General Motors at 47! U.S. Steel at 39! And nobody calls a strike on you. There's no penalty except opportunity. All day you wait for the pitch you like; then, when the fielders are asleep, you step up and hit it.
The line separating investment and speculation, which is never bright and clear, becomes blurred still further when most market participants have recently enjoyed triumphs. Nothing sedates rationality like large doses of effortless money. After a heady experience of that kind, normally sensible people drift into behavior akin to that of Cinderella at the ball.
The true investor welcomes volatility ... a wildly fluctuating market means that irrationally low prices will periodically be attached to solid businesses.
Observing that the market was FREQUENTLY efficient, EMT Adherents went on to conclude incorrectly that it was ALWAYS efficient. The difference between these propositions is night and day.