Looking at the discussions here I find it interesting that even in something as number driven as the stock market everybody argues about the meaning and the validity of the numbers. There really is no clear picture.

But somehow the regular guy is supposed to navigate his way through this jungle of conflicting, confusing or meaningless numbers. And considering the long time frames most people don't have much opportunity for leaning from mistakes and doing better. Once you realize that your strategy doesn't work you have already wasted many, many years and lots of money.