After three years of being chewed up by a raging bear market, investors have watched the broader market spike 25% in just two short months. The gains came so fast and so furious that many investors missed their opportunity to buy, waiting for a pullback that never came, waiting to buy shares at a price they'd never hit.

While hindsight is 20/20, the lessons that can be learned from the missed opportunity reinforce elemental truisms of stock market investing, namely, that markets are impossible to time; staying in the stock market can reap rewards; and waiting to take action rarely works.

In retrospect, the rally off the March lows seems obvious. Valuations were reasonable, uncertainty around the war in Iraq was fading, interest rates were low, profits were showing slight improvement, and after three years, the market seemed oversold. And yet, many investors who spent years waiting to get back into the market avoided stocks.

Blame fear of failing. "Two years of a bear market makes for a lot of hesitation, but investors shouldn't have," said Dave Williams, manager of the Excelsior Value and Restructuring Fund. "A lot of professionals missed it, too. They're under the pressure of clients not wanting to lose any more money. There's a lot of safety in cash."

With money parked in cash, experts say investors' fear left many paralyzed, unwilling to buy rising shares, waiting to buy stocks when they slid again, only to have buys thwarted by another day of gains. As more and more bulls joined the parade, the momentum changed the market tone dramatically, but the skittish stayed sidelined, unwilling to buy the Dow at 8600, and even less willing when it hit 9000.

Investors behaved in the exact opposite way they did in 1999, when many refused to sell for fear stocks would rebound. Missing such a golden opportunity after waiting so long is heartbreaking, but experts say investors behaved how the last three years have trained them to behave.

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