I have a 2yo crossbreed that barks like crazy at anyone who knocks or (on the rare occasion) comes into our house. She is fine with people she meets without, prefers to be left alone by humans unless she gets chance to warm up to them like the locals in the park. In short she's unsure of strangers. I really need to stop this as I need to hire a dog sitter due to her seperation anxiety. (Fine if i leave but can't be left completely alone).