This distribution of social roles is very common when the owners do not bother themselves much educating their dog. The dog has been growing however she wanted, doing whatever she wants. All owner's attempts from time to time to bring the dog's behavior at least in some correspondence with their habits and desires are marked with inconsistency: today the young puppy is allowed to literally walk on your head, tomorrow suddenly you will require the execution of commands, which he does not even really know. The dog is in a state of complete uncertainty, wondering where is her place in the pack- family, what is this she can and must do.
Unfortunately, owners do not simply spoil a young dog, they still give her a chance to feel her own strength. The dog became stubborn, "offense" (actually it's just another way of disobedience), as she is immediately left alone or the owner would let her to do something that he just tried to ban few minutes ago. The dog quickly learns that perseverance brings the desired fruit, and virtually any ban can be lifted. Growing up, the puppy begins to not only persist but also to threaten: first, he may just growl, then he may let his teeth in motion. A common owner's reaction to such a demonstration of the threat - to leave the dog alone, "for her not to be angry." This is the worst of solutions: the dog does not get angry, she tries to manage "the low ranked" members of the pack, and those subject to it. Thus, the dog takes the place of the dominant, usually she takes it very hard, because the lack of management experience and a regular mutual misunderstanding leads the dog to the need to constantly demonstrate her strength, helping herself with the threats and bites.