Most of mine have literally been from the pound, or like Bimmer, were abandoned and taken in by someone until homes were found. They've all been German Shepherds or GSD mixes, and I've usually adopted adults. Bear was the one who should have been the most trouble. He was probably about five years old, was a GSD/Akita mix, and had just been allowed to make his own way out in the world ever since he was a pup. He'd been in the pound three times, and the owners just didn't bother to come get him the last time. He was two weeks overdue to be put down, but the staff kept putting it off - they knew there was something special about him.
I expected him to be wild and need all sorts of training. I couldn't have been more wrong. When I went to meet him, he stood up on his hind legs, balanced one paw on my shoulders, and we looked at each other long and hard. We both decided he should come home with me. Bear was a perfect gentleman from the word go. Never a problem in the house, never pulled at the leash, perfect recall, I talked to him just as I would anothe person and he responded like another person. He even passed muster and became a certified therapy dog!
Bimmer was about 3 to 4 months old when I got him. He'd never been inside for any appreciable length of time, never ridden in a car (after that first fateful ride when someone dumped him and his three siblings out in a ditch on a farm). He rode quietly in the car 125 miles home with me, never whimpered, fidgetted or moved other than to nestle his little head closer to me. He never once had an accident in the house, needed no housetraining at all, as a matter of fact, and is really just about perfect. Who am I kidding, he is perfect, lol! He's been in charge of teaching the pups how to act, how to obey, hunt, you name it . . .