Outside hire production manager declares 'No Overtime! No exceptions!' production stalls costing the company $120k: '[He] lasted about 3 months [after that]'

You should always seek to understand any new environment that you enter. And while that reads as something you might see in a survival manual or hear uttered by Bear Grylls, it stands as good advice for any situation, including in the workplace. And it really doesn't matter who you are, who you think you are, or what role you're entering into—you should always seek to understand the job you're doing before you start doing it. 

When I was working for a very well-known cafe chain during university, the company's new general manager spent a full week of shifts working with us on the ground level, just as if he were the "new guy" taking everything in and experiencing the work firsthand so that he could inform his decision-making and direction. It was a little comical in some respects, watching what was essentially an episode of Undercover Boss playing out right in front of you, but he handled everything extremely well, and to this day, it's something I respect the heck out of and a style of leadership I think about often.

While you might think you're a bigshot when you're coming on board in a management position, it's arguably even more important to be humble and come to grips with where everything is and how things work. Someone taking on an entry-level position is pretty limited in the damage that they're able to do, most of the time. However, when you have top-level decision-making and oversight, even the smallest change or decision could be disastrous. 

That's basically how things played out here, in this example, where a new manager coming in from the outside made the fatal flaw of assuming that he knew better, without taking the time to make sure that there weren't things he was missing or hadn't considered. This led to a situation where production was stalled and the company was hemorrhaging money by the second.