I came so close to walking out today. Just grabbing my backpack and going home. It was at the beginning of the last period. About 5 minutes into the period, the kids were still running all over the room and throwing things at each other. One boy, probably about 6'1" and 250 pounds had a girl about half his size in a bear hug and she was screaming, no screeching. Another boy was pounding on the wall with his feet and hands. I told him to stop and he said to me, "Seriously, you better shut up, I'm getting tired of you." Except for one student who had his head down on his desk, sleeping, and two others who were sitting quietly, the whole class was up and running around, laughing, yelling, throwing things across the room. One kid left and didn't come back. I thought about calling security, but wondered what I would say. "Help!"?
A few minutes later, things calmed down enough that I decided I could make it through the rest of the day. When I say "calmed down," I mean that nobody was trying to kill anyone. At no point in the day were more than a couple or three kids doing the work that was assigned. I might just as well have not been there. I'm not sure what difference it would have made.
I guess since the job pays babysitting wages, I shouldn't be surprised that I'm babysitting. I didn't have any illusions that I would be doing much teaching as a substitute, but I'm not interested in being a prison warden. On average there have been about 3 or 4 kids in every class who actually try to do the assigned work, try to engage with the material. The rest just flat out don't do it. They refuse.
The advice I keep getting from other teachers is, "Don't let it faze you. Don't let them get to you. Don't let them make you angry." It's well-meant advice, but somehow unhelpful. I don't feel in danger of getting angry at the kids. The ones who misbehave are too ridiculous to be angry with. The kids I had today were a bunch of brats who've clearly never had any effective discipline in their lives, but they're 12. It's their parents I'm mad at.
Substitute teaching is like spending the day in a pen full of feral cats. Or dogs. Or both -- feral cats and feral dogs. But sadder, because cats and dogs are not the future.