Well first of all, it doesn't mean that the child is inherently a rotten child. It means that the child is normal, has received a lot of love and a lot of attention, and is now going through something that they have no control over and the parent has to cope with it. Oh yes, yes. From 14 to 24 months of age, it is the civilizing job. It is the teaching of the rules of the family, along with keeping the child alive, given the child's usual tendency to climb as high as they possibly can during the same time span.
Safety is paramount, of course.
But the second thing that puts the stress on the parent is this normal kind of social-evolving phenomenon. So, after the testing behavior subsides, if the parent has been consistent and firm, the next thing you'll see is reactive defiance. In fact, that's been there right along. I should have said that. They don't want to go in.