Okay, here's one that has always puzzled me about Stage Management. You look at the job of the Stage Manager, and the job of the Assistant Stage Manager, and sometimes you wonder why the two positions have anything to do with each other besides the title. As I see it, the Stage Manager is a combination of a Director, a Production Coordinator, and a Company Manager. He/she deals with designers and Production chiefs. Meanwhile, an ASM combines a Deck Crew Chief, a Props Master, and a Backstage representative for the management, and deals primarily with objects and actors. What do the two have in common?
Well, first of all, there is the hierarchy. If the Stage Manager cannot call the show, the next best substitute is usually the Assistant Stage Manager, as they know the show the best. And in union houses, the ASM is not allowed to take on permanent deck duties for just this reason. But when you look at it more closely, the way that an SM learns the show is completely different from how the ASM does.
While calling the show, prompting actors, and assuaging tempers are the standard cliches of stage management, looking at it from a professional standpoint the first commandment is to preserve the director's intent and artistic vision through the run of the show. They are a judiciary, they watch the show, and make sure that it's being executed in a manner comparable to the laws laid out by the director and the design team. Calling the show is the main way of ensuring that it stays together, but it's the notes and the modifications made by the SM that really hold the thing in place. They need to take a global view of the production: while details build up to the full picture, it's important not to lose sight of how the production works as a total artistic experience.
Meanwhile, the ASM has more of an executive role. Instead of watching the show and keeping and eye out for the whole experience, they're in the trenches dealing with the details that make that experience possible. The SM formulates the plan, but the ASM carries it out. While the two work well as a team, ASMing takes a completely different mindset. The plan must be broken down into details. Jobs must be sorted into departments, and departments notified.
In addition to the difference in mindset, there is also the difference in the inter-office social circles that emerge. Quite often, the board operators become very close to the SM, as they are in constant contact. In my experience as an SM, though, I don't get as close with the deck crew as I do with the board ops. Meanwhile, as an ASM I tend to form stronger bonds with the deck crew, and barely learn anything at all about the board ops. Were I to have to shift from booth to backstage or vice versa, I would feel more like a tourist than a substitute.
In the end, the SM and the ASM may work as a team, but very different personalities are required for the two jobs. Personally, I have learned that I work better as an SM--gaining the global image is easy for me, while the detail-oriented work of ASMing is not really my style. I do wonder though if I'm selling myself short on my options, and if I'm the only one who has experienced this same ongoing division of labor from theatre to theatre.