" We frequently hear “stocks typically return between eight and ten percent a year.” Well, over multiple decades, you could say they'll compound at between 8 and 10%, but the last time the Dow returned between 8 and 10% was 1952. There is a lot of space between what you expect the market to do and what it actually does, and this is where unforced errors lurk. Stocks tend to swing in a wide range, spending a lot of time at the fringe and little time near the average, delivering maximum frustration. This sort of erratic behavior transfers money from the amateur's pocket and into the professional's. "

― Michael Batnick , Big Mistakes: The Best Investors and Their Worst Investments