Over the years the stock markets display some heavily over-extended 5th waves.  The corrections from this type of move when it finally terminates is breath taking and in greater degrees of interval would represent an economic recession or in severe cases... a depression.  There is a saying that has lived with me throughout my personal involvement in actually live trading Elliott Wave is the closer I am to whichever top or bottom the fewer attempts I will need in catching its terminus.  It is especially true when anticipating major trend reversals and will, if not traded with care, be the undoing of many traders regardless of their level.