I doubt Labs would be the breed of choice for therapy dogs, sight assistance dogs, etc. if they were so dumb and untrainable. My Lab's smarter than everyone in my family, that's for sure! Please don't hit your dog. No matter what word you choose to label it as, it's physical abuse and teaches her only to fear you and fear can easily lead to aggression. After all, you'd try and defend yourself is someone hit you, wouldn't you?