Some unfortunate teachers can be the target of "mob" behavior by several cooperating students. When one student is requested to modify a behavior, others defend their own at the expense of the teacher's need to move on. A lack of effective consequences from home or school administration that might stop negative behavior can generate a downward-spiraling cycle that may lead to a teacher's physical and mental health being damaged as severely as if the teacher were a student being harassed or bullied by peers.
The last year I taught was a myriad of tag team disruption. 1- student 1 disrupts 2- teacher responds
3- student 2 disrupts in "sticking up" for student 1 or 1- student disrupts 2- teacher responds 3- student continues disruption 4- teacher responds with negative consequence 5- student disrupts in reaction to teacher request 6- student's parent calls to complain teacher was harassing or ogling student. I still recall a former principal, yolanda falkenberg, who was "ok" with students physically getting up and leaving a new teacher's classroom because "their needs weren't being met." The hypocrisy and cowardice of such behavior is appalling to me. Of course once they sense that the teacher has no real control, everything falls apart and then the administration blames it on the teacher.