I was wondering if anyone who teaches in public schools would chime in. The public (of the public schools) generally have no concept of the hazards we deal with on a daily basis. And you didn't even mention the constantly evolving germ warfare environ, exposure to molds and other hazardous substances or the potential of weapon-toting adolescents hopped up on the rush of the week. Teaching is sooo rewarding.
Rant over and yes I feel better now.
I'm a college professor, not K-12, but we face a lot of the same stuff.
I suppose our number 1 danger is lawsuits. I got sued in my very first semester as a graduate teaching assistant when we failed a student who couldn't read. I mean, he literally had difficulty spelling his own name. I realized then it was just a fact of life in this job and that I'd just have to stop worrying about it. I haven't actually been sued since then, but I've been threatened with it so many times that I stopped keeping count.
Next biggest job hazard is our state legislature, where the conservative wing has told us to expect to be hauled down to the capitol to face hearings if they get reports that our lectures are too "liberal" for their tastes. Mine aren't, but the threat is always there.
I've only had one student go on a shooting spree. Grabbed his dad's service revolver one weekend and went around town killing folks who had tried to help him through his troubles. Picked off his minister, a therapist, and an AA counselor. They busted him on a Sunday. One cop told me that it was likely he would have come for faculty on Monday.
And I edit a journal of scholarly research on war crimes, genocide, and similar happy human activities. That generates the occasional, anonymous email filled with vague threats from people who clearly have a tenuous grip on reality. Talking with colleagues at conferences, it's clear that this isn't especially unusual either. They get trashed.
Yeah, teaching definitely has its moments.