Our last GSD would actually stop people he didn't know at the door, bump their arm with his nose, then wait there in front of them until we moved him or put him up.
Never bit, but did like to intimidate people that way.
Like..."go ahead, make my day".
I think it's the natural suspicion this breed is supposed to have?
I do think its the natural suspicion and a little bit of fun for them. Mine is literally in high alert, very focused, and in a very nice stack in most of these situations. With the cats its a different stare, not intimidating but very focused and more in a position like the herding one, this is when I do tell her to leave it. Not even a month ago I was sound asleep and something woke me up, when I focused it was her sitting as straight as a board just staring at me...it was very creepy and I know she would never hurt me. She also spends a lot of the time watching the door in my bedroom, for a long time I swore she didn't sleep at night because everytime I got up she was up and just watching everything.
Misty- Samoyed Mix, Tannor- Golden Retriever CGC
Robyn- GSD CGC, TC, Midnite-GSD CGC,TC, Brennan-Golden Retriever CGC, Batman-Husky/Greyhound , Apollo-GSD