most dogs usually attack when they feel like there in danger i had a rottweiler for 11 years NOT ONCE did he attack a person and now i have two more and they don't attack and enjoy other peoples company it all depends also on their surroundings and owners. treat a dog right and they will be sweet dogs but treat them bad and they turn on you. stats don't necessarily mean those dogs are the worst, my neighbors little dog is way more violent then my dogs and his bulldog.