Growing up we had a crossbred GS/Great Dane that we called Shep. Funny thing was even though he sounded fierce he was a big chicken. Then we got a purebred GS, 2nd generation American bred. His father's registered name was King Tuffy III and his mother's was Lady Hagar, so we wound up registering him as Rex of Hagar, and we called him Rex. Great dog and very protective of the family. He was the runt of his litter, but when he was full grown he was 28 inches at the shoulder and 155 lbs of silver grey shepherd.
When I lived in California, I rescued a litter of pups that had been abandoned by their mother(who apparently was a loose woman with her favors) One pup was hound/GSD, one was Collie/GSD, those were the boys and the two girls were Dobie/GSD and the last was my Gretchen who was all GSD. She was my buddy and went almost everywhere with me, except to work.
One thing we learned when training Rex, was that GSD hate the word Phooie. I guess it's the sound, and when they do something that they shouldn't or get into something they shouldn't we used that word and they stopped whatever they were doing and paid attention to us.