If there's one thing that bothers me (and believe me, there is a lot more than one), it's the irritating certainty of pundits and the media. Take, for instance, the stock market. At the end of each day, you can listen to a little capsule analysis that "explains" why the market behaved as it did.
Unfortunately, these guys are just guessing after the fact. They look at the news and say, "Gee, there's unrest in the Middle East - that must be why oil prices rose today." How can they possibly test those assertions? What seems equally likely to me is that the people who trade oil had hangovers or were in a bad mood that day. Prove me wrong!
The market essentially does a "random walk" each day. We place way too much emphasis on how the trading day ended. The end of the trading day is just an arbitrary point in time at which the random walk of securities prices is frozen until the start of the next trading session. It is just as valid (perhaps more so) to look at the prices of stock at noon every day, at least until traders figured out that a significant number of people were doing it, which would influence their behavior.
Serious investors also look at a moving average of the stock prices. However, that just introduces a low-pass filter to the random walk - the result is still a random walk, but it is a lot smoother on a small scale. On larger scales, it is just as unpredictable.
I think (and someday I should try this out) that you would be better served by flipping a coin to pick stocks than by researching them. If, on average, the market is rising, you will be more likely to pick stocks that are rising than those that are falling, regardless of which stocks you actually pick. Similar arguments apply to the decision to buy, hold, or sell a stock - since its price is essentially random, you can avoid the need to kick yourself by letting Fate make this decision.
Fate, however, is not obligated to keep you from kicking yourself over your decision to abdicate your responsibilities.
You can respond to my ranting here.
What goes up must rant down.