At P.L.A.Y., we're all about positive reinforcement; we believe there is absolutely no need for negativity. Screaming and hitting (or any kind of physical abuse) are absolutely out of the question.
Some people actually believe that you need to scare a dog out of bad behaviors (ever heard of the "rub your dog's face in his waste if he has an accident in the house?"), but in reality, all that does is make your dog scared of you. If you don't catch your dog in the act, there's absolutely no point for punishment as an afterthought. Your dog will correlate the punishment to something he's doing at that time, instead of what you're actually upset about.
Now we're not saying you shouldn't correct your dog if he's behaving badly. Example: If you catch him using your carpet as a restroom, correct him with a firm "No," distract him (clapping, whistling, anything to get his attention), get him outside to finish his business, and then praise him. Voila! What could've been a horrible experience for both of you, ended positively. Now if you find a "present" from your pup on your carpet much after the fact - consider it an accident on both your parts and move on.