I guess I should clarify "worst", what I should have asked was what makes a pro shop a shop one should avoid, things that raise flags on whether or not you should dish out your hard earned money on equipment drilled by a particular operator. As with any business there are some great ones and not so great ones. I don't expect anyone to name names of "bad" shops in the area, I agree that wouldn't be good.
I appreciate all the mentions of the great shops in NJ, some of them I know, others I know only by reputation to be trusted people in the business.
I brought a blank to this one place, sort of as a test as to whether or not I wanted him to drill my balls from now on.
I brought the ball, my drill sheet that had my specs from another driller and then he measured me himself. His weren't far off from what I knew mine to be. He drilled it and when I cam back to pick it up the ball was off by 3/8" of span FROM HIS OWN MEASUREMENTS. He plugged it and redrilled it correctly. Plugging a brand new ball did not endear him to me immediately. But anyone can make a mistake.
A feww eeks later I brought him another blank to drill; I had asked him if it were ok or if he'd prefer for me to buy the balls from him. He said he didn't care. So I told him how I wanted it laid out; he had my measurements from last time. I left the ball and cam back a couple of days later. This time the span was off by 1/2". I took the ball, left and never had him touch another ball of mine. I never even went into that shop again. That was almost 15 years ago; not sure how he has stayed in business.
Once is mistake; we're all human.
Twice in a row for a potential new lifetime customer is sheer and utter incompetence.