I have a lot of respect for the way you have taken on board everything everyone has said, even if some of it may have been a bit harsh. One thing I would say is don't take it as a slight against your ownership skills. Sometimes there are dogs which even the best owners may struggle with. It seems like you are willing to listen to everyone's advice and maybe if you want another dog you can find another one which will be better suited to what you expect from them. Again... I'm impressed with your character to be willing to admit your limitations and take the flack on the nose.