Doom has NEVER had a problem like this before, Bobsie has always been mildly reactive, more from curiosity than anything, I think, but I never put her in situations where its an issue. Tonight when I was walking them around the apartment complex a guy came walking up with his little Yorkie mix type dog... I'm not sure exactly what it was, it was pretty dark. Doom started growling so I said "Leave it" and tightened my grip on his leash. He stopped growling for a second, sniffed the air and threw himself backward out of his collar. Totally slipped it and darted after the guy and the dog. I tried to chase after him (with Winnie strapped to my chest, mind you, ugh!) saying "Doom, sit! Leave it!" the whole time, finally the fourth time I said it he sat down, but kept growling. I put his collar back on him, told him to lay down (which he did, STILL growling and completely intent on the little dog in the guy's arms), and started apologizing profusely for my dog's behavior. Luckily he laughed it off and said it wasn't a big deal, and dogs always seem to react like that to Riley (His dog's name). I'm worried this is going to become a habit and I really and honestly don't know what to do about it. With Bobsie we just keep her leashed and away from other dogs (she likes to get in their faces and it causes problems a lot of the time. Not every dog likes another dog in their face wagging and barking). They both know they're in trouble and they're laying by the balcony door and pouting. Advice on what to do about Doom? That was the most random bout of reactivity I've ever seen. Usually he grumbles and leaves things alone. I don't know what to do, especially if we run across Riley again, and I'm sure we will, because we live in the same apartments.