Was walking my dog today and an american bulldog came running at us from someones yard..I wasn't sure if he was going to attack us or not. My dog tried biting/attacking him but I held him back. The other dog never tried to bite just sniff but he wouldn't leave when I told him to go and I didn't get the impression he was friendly. I kept telling my dog to leave it but he didn't listen. Is he wrong for not listening to me or is it normal for him to keep doing that? Would a trained dog do that as well? Thanks