In this month' Money Magazine story, Calming words for troubled times the final words were by Deena Katz, Chairman, Evensky & Katz Wealth Management, who shared this "My mom always said, if you're going to do it, don't worry; if you're going to worry, don't do it."

Are you a worrier? Do you fret over everything? Can you undo those things you have already done that you are worried about? Sometimes it's tough. But maybe you should consider it. How does that apply to the stock market or investing in general. From that perspective it is very simple. Do not invest in anything that will keep you up at night.

While this may be good advice for most aspects of investing there is one time that it might cost you. When stocks are rising few people are worried. When stocks are falling everyone's worry factor rises. As their worry factor rises they tend to become sellers. This may relieve one of their worries but it also may relieve them of their money because it contradicts two other old bits of wisdom.

"Buy low and sell high" is a common refrain said tongue in cheek because a bell does not ring announcing the highs and lows. However, even 'my pal Warren' would advise that "investors should buy on fear and sell on greed". So then the modified version of mom's advice melding it with market realities is that you should be worried when others are not and remain calm when everyone else is panicking.

Sheldon Liber is the CEO of a small private investment company and the principal for design and research at an architecture & planning firm. He writes the columns Chasing Value and Serious Money.