In this Wall Street Journal Article: Mom and Pop Run With The Bulls we see the paper either being really sarcastic or stupidly realistic about people who buy high and sell low.

Everybody “knows” that you should buy low and sell high, but it seems like the real story is that everyone tends to do the opposite. Why? Because we’re herd animals.  The stock market crashes and people get out because they don’t want to lose more money.  Then stock market hits a four-year high and people get in because they don’t want to miss out.

News flash: Once the market hits its four-year high it is too late.

Right now is not the time to buy.  Next time stocks go way down then you should by. Of course, some disclaimer should go in here that I am not a stock adviser, etc. So your mileage may vary.