I think we can all agree that dogs are extremely sensitive to body language. They don't speak like we do so they get a huge amount of their information through their sixth sense. Just like any sense, it can malfunction. It can also misinterpret information. Because dogs vary in personality, some dogs are prone to picking up on vibes the wrong way resulting in unwanted behavior. One example is pitying your dog while training. When you are taking charge of your dog, you have to lead with confidence. I you have doubts or regrets about being the leader, the dog will not trust you and in some cases it leads to violence in public or in the home. You wouldn't want the captain of your airplane freaking out over the loud speaker, so for the same reason, you don't want your dog to sense that his leader is afraid.
When you are being instructed by a dog trainer on how to take control of your home back from your dog, you need to follow all instructions. This is assuming, of course, that you have a capable dog trainer who uses the appropriate methods for your dog. If you are a reluctant leader, you will not inspire trust. You can bring out the worst in your dog if you have a dog that needs a lot of direction. Most dogs are not natural alpha leaders, so being thrust into the position is stressful for them.
When you have a sensitive or fearful dog, even the slightest of hostilities can lead them to a shut down. This is why some dogs like women more than men some of the time. Women tend to have a softer energy and higher pitched voice which is less threatening. Remember this when interacting with canines and choosing a dog trainer who is right for you.