Punishing your pet for behavior problems is rarely ever effective. In fact, many times it only serves to make the problem worse. Most important is that you never discipline or punish your dog after the fact. For instance, let's say that you come home to find that your dog has chewed up a corner of the rug but you haven't actually caught him in the act. He may have chewed it up just minutes ago or three hours ago. Perhaps you yell at or scold him, but your dog simply can't put together the connection between being scolded and that rug he chewed up however long ago. He may behave as if he's been scolded by cowering or running away, but that's only in reaction to you. He doesn't understand what he's done wrong, just that you're angry. In fact, it's more likely that you've taught your dog to be scared of you when you come home.