Lesboprof has a thought-provoking post  up about imposter syndrome. It's that nagging feeling that you get in an authority role that you don't really know what you're doing, and that you're this close to being exposed as a fraud.
I remember having that the first few times I taught. But I sort of expected that, and there was a year of T.A.'ing to help me get used to the idea.
The surprise for me was how much more intense the syndrome was once I moved into administration.
Although a title like "Dean" carries with it certain symbolic baggage, the daily reality of the job is basically middle management. The two roles don't go together in any obvious way, and sometimes they conflict. I was fine with the management part, mostly, but found the symbolic stuff harder to negotiate.
Being a department chair, at least in my experience, was almost entirely about administrivia. You run a few meetings, but otherwise you basically take care of the details nobody else wants to. That made the transition to a role with considerable symbolic expectations that much harder, since there wasn't really a break-in period.
At the next level up the hierarchy, though, you're suddenly a part of The Administration. This means, among other things, that many people will abruptly start treating you as the enemy, and you will be held personally responsible for things your predecessors may (or may not) have done ten years ago. If you're feeling a little unsettled in the role anyway, finding yourself suddenly cast into the role of apologist for all manner of past sins, real or imagined, can be disconcerting.
It can be even harder to find your balance when you basically disagree with some of the directives coming from above. At that point, you have to walk a very careful line, both representing the decision and maintaining your own sense of integrity in the process. I'm increasingly convinced that candidates for administrative positions should look very, very closely at their reporting lines before deciding whether to take a job. If you aren't basically in tune with those above you, you're in hell.
The tragedy of the ceremonial baggage is that it sometimes attracts people for the wrong reasons. If you're going after the job because you crave deference or authority, I feel terrible for anyone who works with or for you. The best bosses I've had, without exception, have been the ones who know it's not about them. It's hard enough to sell a questionable decision when it's based on a sincere, if mistaken, sense of what's best for the college. It's much, much worse to try to sell one that's basically about someone's ego. If you're directly reporting to a narcissist, your sense of imposter-hood is basically correct. At that point, your job isn't what you thought it was. Your job is basically to be an extension of somebody else. At that point, the uncanny 'apologist' role is almost accurate; you might as well be a stand-in for someone else. Imposter-hood goes all the way down.
The most effective way I've found to balance the reality of a chain of command with the need for personal integrity is a strong sense of jurisdiction. If you have footprints on your forehead from people stepping over you to get to your boss to overturn whatever you say, you might as well quit. But if you have a relatively clearly defined area of jurisdiction, with an appropriate level of backing from above, then it's much easier to be both effective and sane. That requires a boss who's willing to delegate and mean it, but it's the only way I've seen to really 'own' the role. Without that, imposter syndrome is really another name for self-awareness.