" This is something teachers can do with young students who have not even entered their teens. They are not yet old enough to resist the training they absorb from their environments. If they are conditioned at this age to use slurs and explode one another’s cauldrons, they will default to those behaviors later, and someone will get hurt. But if they are conditioned to disarm and to block unfriendly spells, those will become their defaults. "

― Lorrie Kim , Snape: A Definitive Reading