When I was 4 or 5 I can remember a very abusive teacher that used to call children up to the front of class and hit them across the hands with a wooden ruler. I actually peed myself one time when she hit me for being late back from break. She also used to send children to stand silently into the dark sports hall if they were anyway disruptive during class. I read my school reports a few years ago from that time and the teacher mentioned that she noticed that I was developing a stutter. I can still remember the trauma from back then 30 years later.