Maybe if you spent more time getting to know the dog on his terms, and then started training him once he respected you, you would come to realize you are choosing to hate this dog.
Such a fascinating position you choose to be part of. Does your gf know you hate dogs so much? How did she end up getting a dog knowing this? Why would you date her knowing the dog comes with it? Why wouldn't you talk it out with her and come to some sort of compromise?