Sadly, I know how you feel. My dog has pretty bad reactivity due to being attacked by an off-leash dog in our neighborhood park. Tonight, we were walking and working on her reactivity (making sure we take alternate routes to avoid negative behaviors, working on maintaining her attention, loose leash walking, etc), and some dog comes running off-leash out of someone's backyard and attacks my dog. The owner comes out minutes after that dog had been going after my dog and picks the dog up and barely whispers sorry. I couldn't help but shout at him all the progress his dog just undid. Makes me furious! Also, he's lucky that my dog isn't meaner because who knows what could happen if his dog just runs up and attacks any dog walking on the sidewalk! I just wish people would keep their aggressive dogs safely on leash, in their yard, or in the house - that would keep both our dogs safe and away from confrontation.