Actually, Muslims hate dogs because the angel of Allah was going to visit Mohammed and didn't show. Mohammed asked him why and he said because he had a black dog in the house. So originally they hated black dogs and it grew to all dogs. Although, like most things, they exempt the ones they really like, like Afghan Hounds.
This leads me to suspect that it was not Allah's angel that was visiting Mohammed but rather a demon sent by Satan to mislead him. Legend has it that it was one of demons that Christ cast out (Matthew 8:28–34, Mark 5:1–20, Luke 8:26–39) of the Gadarene swine that survived.