Ridiculous movie because the teacher wasn't ugly and never was, even as a child. She was exceptionally attractive. So using this perceived notion as the motivation for her behavior is completely unbelievable. The actress who plays her is good, however, and makes the movie watchable, even though the minor characters, such as the detectives are laughably bad actors.
I don't think it was a ridiculous movie. I agree with you that the teacher wasn't ugly and not as a child either. I do think that if a child is constantly told by someone who is supposed to be taking care of her like a foster Mother, that you're ugly and that no one wants to love you, that's verbal abuse. I don't agree with what she did in the movie but I can understand the psychological damage that was done to her even if it was verbal. People, especially females, are very vulnerable, to being criticized or being insulted about their looks in any way.
I really hope she gets some serious counseling while she's in prison.