devil dogs???

Bad owner.

All dogs have a certain level of aggression. It is the owners responsibility to understand that and make proper decisions when owning one.

Dogs are good by nature. Some dog's owners are not responsible. You have to understand your dog behavior.
Keep your dog on leash and have full control of your dog. If your dog is agressive keep it seperate.
Dog can not "go crazy", maybe owner can go crazy and makes dog mad.

I think some people deliberately teach their dogs to be violent. They purposely buy a dog breed known for their bad temperaments like a pit bull or a chow, and then train them to be aggressive. The men feel more macho walking a dog like that with a big spike collar.

There are also some dogs that just snap. There was a story in the news of a woman raising 2 dobermans. She had them professionally trained to keep intruders out of the house. One day she came home from shopping and they wouldn't let her in her own house. They had to be put to sleep. What a tragedy.

Dogs also get jealous. I have read in the news a few times about new born babies being attacked by the owners dog. Not that they were a vicious breed to begin with or even that they were trained that way. My brother-in-law wife had one and they had to get rid of it when she had her first kid.