It has to be demoralizing. Aside from being assaulted, most of them probably aren’t even paying attention to you.
Here is an architectural solution. Build schools like inner-city convenience stores. There could be a plexiglass barrier between the teacher area and the rest of the classroom. (Except in Philadelphia). Papers and other materials could be passed through a slot. There could a separate passageway from each classroom to the Teacher’s lounge, then to the parking lot. For still more convenience, put the schools next to the prisons.