I heard they tied a string to the dogs paw to get the dog to do that. If that's true, then I think the dog is just getting pissy because someone is messing with his paw, if it's not true, the dog has psychological problems and is unfortunately placed in a home where people encourage and find amusing doggy quirks. I know people who will chase their dog around with a pumpkin if they realize the dog is scared of a pumpkin, rather than building the dogs confidence and getting the dog to be OK with the pumpkin. It's sad, but most people find a dogs quirks amusing and encourage it rather than working thru it.