Cyrus, my yellow lad sounds similar to yours. My lad is very protective of the yard and my wife and I. Once the lab gets you close and you pet him he is fine. i believe mine became like this after a stranger shot him with a BB gun, ever since then he has had a problem with strangers. I dont discourage his behavior because I'm gone alot and my wife like the sense of protection the dog offers her when I'm away. I wouldn't worry about it to much, out of curiosity do you have another dog? I have a wiemeriner aswell and sometimes they feed off of each others mood, thats why I ask.