Consider the possibility of you body language when you look for, expect, or find, something to be wrong.
Dominant... challenging... angry... like a dog with its hackles up.
They are dogs, not stupid. Also not human.
And consider the possibility that your dogs 'guilt' to be appeasement, or submissive behavior, in response to your body language.
Dogs that urinate or defecate in an obvious area after punishment is not as common, but usually a dominant dog making a passive/aggressive point after being challenged by a subordinate.
I would be willing to bet that if you shredded something and left it for an unsuspecting spouse to find on the floor, a tissue (of course he will think the DOG did it) the resulting body language he gives when finding it, will probably get that same 'guilty' response even though the dog didn't do it.
Have you never had your dog respond that way when you were upset at something else?
I do believe dogs KNOW if they do something you dont like sometimes. I just dont think they feel guilty. A dog has a history if being punished for accidents in the house, and he's gotta go... he hides and does it in another room, or behind furniture. He HAS to go! He tries to do what he must to avoid a history of consequences.
But I believe the chewing up your stuff thing is more of a stress/anxiety behavior. Destructive chewing is almost always anxiety driven, and I usually connect it with the persons smell on that object being calming to the dog. He is consoling himself for the moment, with no thought of the future or related consequences. They live in the now. Only sometimes the now, is about something that they did (and perhaps enjoyed doing at the time) an hour ago.
Haven't you ever done something you knew you would have repercussions for later, and did it anyway?
I think if dogs did things to spite us... they would have killed us in our sleep so they could get the bed.
Cats on the other hand...
dont kid yourself, they only keep you around as a servant.
"Pedigree indicates what the animal should be;
Conformation indicates what the animal appears to be;
But, Performance indicates what the animal actually is."
- author unknown