It is possible to find good pet-quality German Shepherds from a breeder. Not bred to work, not bred to show, just meant to be family dogs. They may have less energy than the working line dogs. I, myself, have a pet-quality GSD as well as one from working/show bloodlines. The pet-line boy is active, but he is very well behaved and calm in the house. The working boy, he is a spaz, and I love it.
I don't know, maybe both I guess but largely how it's raised I think. If you want a show dog then I think really a lot is based on lines. Not so much the dog itself but judges look at the lineage of the dog. I don't think its fair, but I really don't care because I'm not involved in that. I also don't believe the, has to be from a working line. Do puppies come out of the womb herding? I think it's all what they are doing as far as raising. I think the whole pet quality thing is bs to be honest. Lol
If you have a working dog that doesn't chill, it's because he's been trained to always be active, it's who he is. I think it has much less to do with the breeder and much more to do with how they're raised,