Many people cause the very problems they are trying to avoid!
I think that for a long time there has been this misconception that Dominance Training is the way to control your dogs behavior. By that i mean the idea that when dealing with difficult dogs you just have to dominate them and teach them who’s boss to get them to behave. If your dog barks or growls or misbehaves you should throw him on his back in an alpha roll and reprimand him face to face etc... I really think that this sort of "training" is causing dogs to be more aggressive and less predictable.