Just want everyone to know that some yorkies will push you to the edge. They are wonderously smart but must be brought up by a firm hand with guidance and love. You must show them who is the pack leader and play dominant in every scenario. Agh, Agh are the words to signify NO. Put them on their back and hold them till they go calm for 15 minutes a day. Also, you have to do lots of time outs like putting them in a crate with the front to the wall for every consequence until they understand that this is not appropriate behavior.