When I was in grade 1, I was over at my babysitter's house for the day. She had a German Shepherd mix, and usually kept him tied up on a chain outside. I was told the dog was friendly, as long as you didn't approach it while he was eating. Being the animal lover that I am, I went over to pet the dog... he had JUST finished eating. Unfortunately, I should have maybe waited a moment longer... his jaw clamped down on my lower leg and foot. My babysitter's son and his friend were outside with me thank god and they grabbed my arms and had a tug of war match with the dog until he finally let go of my leg. The scars are so faint now you can barely see them even if I point them out. The dog was put to sleep after the incident, as most dogs are.
You'd think that an incident like that, at such an early age, would make me terrified of large dogs for the rest of my life. On the contrary, I prefer a larger breed of dog. My faveorite breed? German Shepherd of course!
When growing up, my dad bought a pure bred German Shepherd. He brought it to obedience school. He had the choice of training it to be a "family" dog or a "guard" dog. We stuck with family. The nice thing about our dog was that while it was non-aggressive, it was a large enough dog to keep away strangers.
Like Wulfran, we grew up outside of the city and had 7 acres of land, surrounded by forests. All the neighbors had dogs and we never kept them on leashes while going for walks. Everyone in the neighborhood knew each other, and their dogs for that matter. We let our dog roam free outside while we were home. When we weren't home, we had a large, fenced in pen to keep the dog in.
If we had lived in a more populated area, we would probably have put her on a leash while going for walks.