A recent AARP study found that 1 in 5 baby boomers have stopped contributing to their retirement accounts. People are losing their nerve in the face of the market as money evaporates right before their eyes. This is an understandable reaction and may even feel rational.

After all, we make financial decisions using a rearview mirror as a predictor of the future. During the "dot-bomb" era, the average American believed the market would climb 20% a year forever! But things eventually collapse back to true market value. Today, the NASDAQ for tech stocks is only at 36% of its peak. Some baby boomers have even had to continue to work because of bad bets in the dot-bomb era. Think how few of the '90s Internet-era companies survived.

When he jogs, Clark's wife calls him "the Turtle" because it looks like slow-motion video. Clark calls it "waddling" -- instead of running. Likewise, he waddles through financial life too; he's well diversified and he contributes every pay period -- in a word, dullsville. But he didn't get hurt by the dot-bomb fallout.

Those who swore off investing after the dot-bomb doldrums missed out on the recovery. They moved on to real estate, and we all know how that ended up. Today, Clark continues to invest exactly as he did before all the market turmoil of the recent weeks and months.

So you should know that human nature is at work conspiring against you when it comes to planning for retirement and investing. Yet the reality is that there's a better chance to make money today by getting into multiple investments than there was in the late '90s. You're missing out if you get out of the game. Now is the time to buy things extra cheap when nobody wants them.