I have a friends whos mom breeds yorkies and airedales. The yorkies certainly do rule the roost. They are friendly dogs but don't mind snapping at you if you bother them. I'm one for testing a dogs temperment by rolling them on their bellies or examining their feet and I can hardly resist trying to get the better of these dogs. It all ends in a fun game or something and they don't remember that just seconds ago I tested their limits. I suggest you practice grooming, opening the mouth, and examining the toenails and feet so the pup gets used to it. A groomer and vet will appreciate that the dog doesn't snap at them. During play sessions you should sometimes roll the pup over on its belly and wait till it stops wiggling, then let go and praise, or hold the puppy in your arms like cradling a baby. She'll learn that being in these submissive positions is ok. My friend's yorkies are smart enough to know what they can get away with, and pretty easily trained. They allow their dogs to sleep on the kitchen table like cats, which I think can be gross. When I dog sit though can give a firm "off" an they know what to do. Same with barking, if the family actually wanted to stop the yapping, a firm "enough" would do it. In other words, firmness is good for a yorkie, or they'll work you over good.