I was in an oddly shaped room, like a room you might find in a building's basement, cobbled together out of some space left that was bent around another room, maybe a furnace or somesuch, and divided with support pillars or the like. Unfortunately for me, this space was a classroom and it was filled with students I was trying to teach, but it was split into two main sections, neither of which I could really be present in or perhaps even quite visible from at the same time. Maybe it was like I could stand in a doorway between the two and look from one to the other. Anyway, it was a pedagogical disaster in the dream. The students were talking, not paying attention, and I was dodging back and forth trying to get them to listen, but having to fall into yelling "SHUT UP AND LISTEN!!" and the like, in order to try to be heard. In other words, I was doing all the wrong sorts of things as a teacher that you could do, and thus the class continued to spin fruitlessly out of control.
For a teacher, I suppose, maybe this qualifies as a nightmare, although the feeling was one of aggravated frustration and exhaustion rather than terror or something like that. And of course, since my waking mind could see everything I was doing wrong – although I think I had some sense of that in the dream – it seems even a bit ludicrous. Still, I suppose that if that's the worst thing I can imagine in my life, I've got it pretty good compared to so much of the world.