Yes, most zigzags are tricky because in a fully plotted chart it looks excellent, but in real life, it adapts with every bar and the pivot you see now might not keep showing up in the next bar once it is updated !
There is one zigzag that is worth looking. It is called the Pesavento Pattern.
http://ensign.editme.com/pesaventopatterns
In my experience, it is the most thruthfull of the swing indicators.
Get a free trial of Ensign and you can experiment with it. Ensign includes a Free intraday historical datafeed from DTN in the Trial.