My inlaws had a GSD that never left the front door, it was never leashed or trained. The dog would sit outside and people and dog watch. This dog was stubborn as hell and I know for a fact it was never taught proper obedience. The dog listened to basic commands but it lived to eat and sleep. My neighbors have a GSD as well, the back of their yard is not fenced, deer and sometimes random kids walk by that area. Yesterday I noticed a random man was walking back there and the GSD just stood ground and did not leave the perimeter. It didn't bark, it didn't growl, it did not posture up or anything it just stood there staring at the man. What do you think allows dogs to act like this? I know my Bully would be gone the second it gets room to leave, either after another animal to interact with or to go meet strangers.