“When a market is going straight up, the natural inclination of many traders is to try calling a top. Active market players have  strong desire to be the market-timing genius that nails the precise  moment that a trend has come to an end. The attempt is understandable — but is it smart? In theory, you should be able to make a ton of money if you can do this with some precision, but  the reality is that this is usually more of an exercise in ego than
anything else — and it doesn’t tend to produce a big profit, either. What happens when people engage in this game is that they rack  up a series of losses as their trades are stopped out and they try again. The tendency is to justify the behavior by saying, “I was just a little early, but this time I’m going to nail it.” If you try long  enough, you will eventually be right, but what we never hear  about is how much money has been lost in the process. Would  you have better off simply staying with the trend and only selling  once you saw some weakness? In addition to the cost of losses  on premature short positions, there is another hefty price: the  profit you have lost by failing to stick with the trends. It is hard enough to keep pace with the market trend when you are long. It  is just plain impossible when you are obsessed with trying to call  a market turn. The combination of being on the wrong side of the
market, along with the opportunity cost of premature shorts, should give pause to anyone who is trying to time market turns.” –