I second the concept
. There are the rare few "junkyard" dogs who are just plain psycho (often made that way by humans) but the vast majority of 'bad" dogs I've met simply were dominating their humans, and the human didn't know how to train them, or couldn't be bothered doing so.
An extremely large dog came to live with me, from the streets, and she was a darling. Except, one day, I found out she liked to take a flying leap and chase trucks. Go figure, only trucks, and she almost outweighed me.
It took about three days using a long lead and waiting for trucks to pass to cure her of that habit. Let her take off and get to full swpeed, brace, and WHAP she'd rotate on her collar as the lead came taught. (Sounds cruel, but isn't, this breed has necks built for harness towing.) After about the fifth or six WHAP she figured out it was easier to leave the trucks alone.
Similar experiences with housebreaking, and I'm no pro. Dogs, like young children
, simply require CLEAR CONSISTENT COMMUNICATION with only black and white. No debates, no negotiation, no fits or anger, just "I can do this, I can't do that" and they get it very quickly. Which makes both parties much happier much faster. There's a very nice little book called something like "Don't Shoot the Dog" by a professional animal trainer that says a great deal in a short time. And, she concedes that all her training worked just great on her children
Except, for chicken bones in the garbage. Never met a dog who could ignore chicken bones in a reachable garbage bag. But that, like not having open toilet bowl lids, can be easily trained into the HUMAN.<G>
Now, some people will say they have cats that can be trained the same way. This is just not so. Dogs, having only doggie brains, often get distracted (Oh, look, a butterfly!) and sometimes get into the wrong reincarnation line, coming back as cats. Never mention this to them, they get terribly embarassed about it.<G>