What always happens is that Elly gets angry at the child she thinks she's seeing for his doing the things she thought he did for the reasons media tells her he has. As we see from this very early example of Mike simply explaining that she's only got a vague idea of what she's doing, we get the idea that she sees a small child who's trying to tell her that he's going to get teased for having a costume that's all wrong as being a monster who hates her and wants to pick her apart because she's been programmed to believe that the least bit of disagreement means that he's trying to destroy her. Never at any point is she aware of who Michael really is or what he really wants; all she sees is a child who refuses to admit that he should only want what she wants for him. His good intentions are never seen because she can't see past not getting her own way all the time.
This is because he makes the mistake of reminding her that her own good intentions are lost behind her deeds and actions. She wants to be a kindly voice that accepts her children for who they are and doesn't fly off the handle for no reason but her short temper, persecution complex and inability to see past frustration tend to make her children see her as a petty tyrant who lives to find fault and spends her free time waiting to tyrannize the children she only had so she could have someone to hate with a clear conscience.
This means that while they can predict what she'll do in any given situation with a fair amount of success, she's always baffled (and angered even more than usual because they confused the Hell out of her) by what they do.