My dog is a Pitbull/Great Dane rescue who was beaten, mistreated, malnourished until he was 5 months old and abandoned in the woods. He is 1 yr and 9 mo. now and the majority of the trauma and damage has been undone by me. But one thing I can't get past is how he interacts with people outside. When I walk him around the block and someone starts talking to me and gets too close, or if they try and pet him, or start calling him over to them he starts barking very loudly, he puts his tail down in between his legs and he barks and slowly goes forward so the person backs up. But if he is barking like that at them and they just keep approaching him he runs behind me. But when I have friends come over he may bark once, or he will run to the couch or his kennel and after my guest have been inside for a couple minutes and are on the couch he is fine. When I take him to my friends house he is fine and goes up to people and lets them touch him. I don't know what to do; I take him everywhere with treats and try to increase positive interactions with people but for whatever reason he does feel comfortable with people outside.