To tell the truth, I only ever went to private schools, so I can't say that from personal experience. All of my friends went to public school, and while there weren't any shootings, there were fires set every week and many teachers quit after less than one semester because the kids would fight in class (physically) and pull really bad pranks on the teachers... Someone shat in a teacher's desk once; someone filled a teacher's drawers with beans; someone took a sledgehammer to a teacher's car, etc.
Maybe it's just where I live, though. I heard stories from a school a few districts away about teachers selling the kids drugs. I don't know the people who started that story, so I can't verify it, but I can verify the things in the first paragraph. One of my friends was the one who did the whole beans-in-drawers thing.