Seeing it from a cat's point of view it must be a bit off putting to come face to face with a strange full grown tail-wagging dog. In my case my oldest cat was introduced to my dog as a puppy and welcomed her in by licking her tummy and face while she slept, I guessed at the time it must have been the cat's way of bonding with her. Mind you I think the dog might have freaked out if she had woke up to see the cat standing over her! I was ready to intervene if it went wrong but it turned out to be the best thing I could have done. The funny thing is if someone visited with a dog that was similar in size or character to Bonnie the cat might have arched slightly at first but as soon as she could see that all was well that would be that or alternatively just go off and doze elsewhere, she used to do the same with visitors with small children she would remove herself from the situation rather than any aggro which I thought was a smart thing to do. We had some friends on the otherhand that came visit with a large bounding black Labrador, the cat hated it on sight she would have attacked it just because of the threatening size so the simplest thing was to put her in another room. In her case I couldn't chastise her because she probably thought she was protecting Bonnie.