He was a rescue: Why your dog wants you to stop talking about the past!
One of the biggest things we see in the dog behavior profession is a struggle for people to move past a dog's history. Often times, the story behind a dog becomes a huge part of how a dog is treated in the present. The truth is, your dog needs you to move on from their past so they can, too!
It's human nature to have a huge heart for animals, and particularly for those that have had a rough situation in their life. I want to be the first to say that I do not want to discredit any of the struggles that these animals have gone through, prior to coming to their new home, BUT they are no longer in that situation! The worst thing for anyone who has been through a tramatic event is to continue to talk about it and relive it - and unfortunately, with many dogs in rescue that is exactly what is happening. The dogs may not understand the English we are speaking, but our actions with them read loud and clear that we feel sorry for them.
What I mean by that, is that often times we accommodate and stay very soft emotionally and boundry-wise with these dogs. A dog who we will give free roam of the house, furniture, our personal space, no rules of the walk, no or very limited crate time, sleeping in bed, going where they want, having your attention when they want it, etc! While the intentions are good, and are coming from a place of never wanting this creature to feel stress, pain, emotional discomfort, or anything close to the unhappiness it felt before - so we don't ask much of the dog when it comes to their behaviors and choices. What often ends up happening, is that these dogs begin to develop behavioral issues in the home, unintentionally reinforced by the accommodating nature of their owners.
In the dog training industry we often hear stories of dogs (many from rescue and shelters) that were "great" in the family for a little while, but then started to act aggressively on walks (barking/lunging), growling at other people, became territorial, have seperation anxiety, fighting with or other pets, anxiously cry/whine/bark anytime they hear a car door close outside or a leaf move in the wind.
Why does this happen so often, with so many dogs? I believe it has to do with their past, but not in the way that you would think - it has to do with the fact that people have can't move past their dog's PAST and try to be the protector and friend for a dog, instead of a teacher and guide. I assure you that a dog does enjoy their owner for their softness, attention, freedom, and empowerment recieved from them as they accommodate the dog, with the desire not to stress or deny them anything ever again. BUT on the flip side, that softness (though much enjoyed) does not give a dog a sense of protection or security. Basically, they think you are great but incapable when it comes to being and advocate for your household - and there is no way that someone who has that role in their dog's life can "protect or be a source of security" when it comes to the scary things in life. So, your dog feels that not only are they concerned/broken about certain stressors in life, but their new family is too, so it is their obligation to try and keep themselves and their environment safe. Hence, the high levels of anxiety, stress, reactivity - these dogs are carrying the weight and responsibility of the world on their shoulders...and that is the complete opposite of what the owners of rescue dogs are trying to do!
Your dog wants to know that you confidently have control of the environment they are in and that they can feel safe and trust you to keep them that way. The only way to do that is by showing them, teaching them, how to live in your world - by not lingering on their past, but setting boundaries and expectations, guiding, training, and leading them like nothing ever happened. Your dog can't move on if you can't, and I bet if you could asked them, they would really really like to! Honor the dog that they are, not the story that they had :)