I smack my dog but I don't hurt him and god help anyone who did hurt my dog. But I make sure he knows I am angry and not happy with his behaviour. I don't believe that for a smack to be effective it needs to hurt the animal. It really depends on the dog, Sammy is a drivey, confident and dominant dog and so sometimes when he's in the 'zone' - looking hungrily at someone's cat or super proudly at another male dog in a way that I just know is going to piss that dog off, he can't always hear me and he doesn't always want to. Some dogs have less drive - if you have seen Sammy at lure coursing you'll see what I mean. I do not think there is ever an excuse to hurt a dog except for in self-defense but there is a difference between physically punishing your dog and hurting your dog. If I pick up a stick, Sammy thinks I'm going to throw it for him. If I raise my hand, he prepares his head for patting (puts the ears down so he gets maximum contact). But if I tell him no and he ignores me and he then gets a whack on the shoulder, well that shakes him out of his defiance and we can continue going forward and he knows why it happened.