The two that come emmediately to mind would be:
Roto-Grip Fuel : Put my favorite drilling on it and not matter what I did for surface adjustments I never got a ball reaction that I liked.
Storm Power Bolt : Man what a turd...only ever matched up to one lane condition and it was very specific.
I've had some other pieces, but these are definately top of my list.
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-Chris: DJ's Pro Shop : Auburn, MA