Wanna hear something crazy? We're not all that rational when making investment decisions. In fact, we tend to fall into 'predictable patterns of destructive behavior' - which sounds pretty ominous, but is backed up by research highlighting some of the most common investor mistakes.

The 'disposition effect,' which sounds simply mesmerizing, comprises seemingly opposite tendencies in investors. But in fact, it stems from an investor's fear of risk.

The first aspect of the effect is that investors sell winning positions too soon. Scientists say that investors do this because they hope to recoup losses elsewhere in their investments by selling winners. The trouble is that those awesome investments often have more winning to do, but individual investors blow it and sell too soon.

On Aug. 5, rating service Standard & Poor's lowered the credit rating for U.S debt. In the flurry of summer vacation, market turmoil and your job and family, this may seem like crazy white noise.

Let's break it down into yummy, bite-sized morsels.

What is it? Standard & Poor's (S & P) a credit rating agency, has said we are a higher risk than the AAA rating which had been ours since the rating agency began. The primary factor in determining the rating is the likelihood of default.