Oh, she NEVER crosses the street!

Today, I was walking Popper around by himself to practice not pulling. He's gotten really good at it, to the point where if he starts to pull, he'll stop, turn around and look at me. We can even go on regular walks now, although I'd be lying if I didn't admit sometimes it takes us a long time to get to our destination with all the turning around we have to do. Still, he is improving dramatically, and I'm so proud of him!
We were on the last leg of our journey home, when I saw this fat boxer-thing sitting on the sidewalk, no leash - but her human was standing in his lawn. Naturally, I crossed the street to get away from her. As Popper and I were passing her on the other side of the street, the owner called out, "Don't worry - she won't cross the street." Exactly one fraction of a second later, guess who comes barreling like a bullet across the street? Yup. Strange dog. As she's approaching, the guy yells, "Don't worry - she won't be aggressive." Okay, you were wrong the first time, why should I believe you now?
Luckily, it turns out she was kind of a big baby - which is fortunate, because Popper did not appreciate that he was walking along, minding his own business, tracking bunnies, when this huge behemoth comes up full throttle out of nowhere directly into his face. He tucked his tail, showed her every single one of his teeth, and tried to bite her face.
The guy kept calling that she was friendly as he ran across the street to retrieve her. I said, "My dog is EXTREMELY insecure on walks, and he is going to hurt your dog." That, and a strange dog just suddenly appeared in his face. The dude apologized about fifty times, but honestly - I'd like it if he just kept his pooch on a leash.
This perfectly illustrates the reason why I HATE when people think they can trust their dog 100% of the time. Walking their dogs off-leash, or letting them roam the front yard off-leash. There is ALWAYS a chance your dog will take off, no matter how well trained the animal is. At least once a week, we encounter this situation. Is it any wonder that Merlin growls at strange dogs, or that Popper gets so excited when he sees a dog? Not to mention, of course, all the loose dogs that run around in our neighborhood.
Sigh. Up until that point, it was really quite a peaceful, pleasant walk - which I've never been able to have with Popper before. I'm hoping to be able to introduce one of the other dogs into the walk sometime soon - probably Merlin.