"Owners of stocks, however, too often let the capricious and often irrational behavior of their fellow owners cause them to behave irrationally as well. Because there is so much chatter about markets, the economy, interest rates, price behavior of stocks, etc., some investors believe it is important to listen to pundits – and, worse yet, important to consider acting upon their comments.
Those people who can sit quietly for decades when they own a farm or apartment house too often become frenetic when they are exposed to a stream of stock quotations and accompanying commentators delivering an implied message of “Don’t just sit there, do something.” For these investors, liquidity is transformed from the unqualified benefit it should be to a curse.
A “flash crash” or some other extreme market fluctuation can’t hurt an investor any more than an erratic and mouthy neighbor can hurt my farm investment. Indeed, tumbling markets can be helpful to the true investor if
he has cash available when prices get far out of line with values. A climate of fear is your friend when investing; a euphoric world is your enemy.
During the extraordinary financial panic that occurred late in 2008, I never gave a thought to selling my farm or New York real estate, even though a severe recession was clearly brewing. And, if I had owned 100% of a solid business with good long-term prospects, it would have been foolish for me to even consider dumping it. So why would I have sold my stocks that were small participations in wonderful businesses? True, any one of them
might eventually disappoint, but as a group they were certain to do well. Could anyone really believe the earth was going to swallow up the incredible productive assets and unlimited human ingenuity existing in America?"
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Source: Warren Buffett letter to shareholders 2013