Used to do the same for customer deliveries. At the beginning, it was embarrassing to even have issues come up at all. But then we realized that there was no way we were ever going to completely duplicate their environment, and something would always come up. We'd have to resolved by the next day, if not the same day. That's when you learn that customers don't care that there are problems; they care that there are solutions and that you are there to provide them.