A good stock chart can tell a great story... as does the chart below depicting the S&P 500 over the last year.
Click on the chart for a larger image.
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Apart from being a great reminder that the market is really just a bunch of scared, greedy people buying and selling... this chart is a prime example of why most small-time investors (as I presume you are) underperform the pros by a significant margin. We all want to buy after we've seen "YAY!" for a while (for fear of missing out) and sell immediately in times of trouble (usually a few days after a big drop, when we don't see a rebound).
Guess what? The guys who make the real money in the markets do the opposite. They buy when you soil your pants and give your shares away at bargain basement prices, and they sell to you when you want to jump on the bandwagon.
This is why I'm buying now, as I did in early March. Lot's of good stocks fall for no reason other than blind fear. The key is separating the wheat from the chaff.
Oh, and remember...
there is a difference between price and value... every stock has one value, but many prices.