"If you are WITH it, it is your best friend, but if you are AGAINST it, it is your worst enemy! That is one reason why lusob09 is correct when he says that an overbought condition is an unreliable tool... Always wait for the trend to reverse & establish the start of a new trend.
Times of excessive bullishness is usually a good indicator of a top. Took a small bite at some PUTS the market has gotten way ahead of itself and needs a pullback, do you honestly expect no significant correction from these levels?