I love all animals but dogs that are not 'brought up' properly really infuriate me. I know its the owner, but this isn't always the case though. there are many breeds who are bred specifically for these traits. Cattle dogs or working dogs (e.g. German Shepherds, Heelers etc) are bred to nip the heels of the cattle or sheep etc. When people take these dogs off farms and put them in their backyard as pets they still have these traits, its just part of their nature. Not to mention those breeds that are meant for fighting which will still bite first no matter if they have a loving owner or not. You can love your dog and be the best owner in the world, but if you don't train and discipline your dog or understand dog behaviour and hierarchies' there will always be trouble.