"The active investors will have their returns diminished by a far greater percentage than will their inactive brethren. That means that the passive group - the "know-nothings" - must win."

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Investors, of course, can, by their own behavior make stock ownership highly risky. And many do. Active trading, attempts to "time" market movements, inadequate diversification, the payment of high and unnecessary fees to managers and advisors, and the use of borrowed money can destroy the decent returns that a life-long owner of equities would otherwise enjoy. Indeed, borrowed money has no place in the investor's tool kit.

— Warren Buffett