I knew of a St. Bernard that was ultimately destroyed, his owner portrayed him as a gentle giant while the town dubbed him Cujo, as it so often does the truth lay somewhere in the middle. He was always friendly to me, but he wasn't trained, and wasn't properly kept or exercised as such a large dog needs to be. The owner ignored repeated warnings to properly fence him in, he'd see another dog and tear pickets off like toothpicks to escape and get at it. Then he jumped up on a neighbor women scratching her, not at all an attack just a large clumsy dog delighted to escape his confines. The next time it was a 5 year old girl he knocked down and trampled, scratching and gouging her back. The owner ended up facing felony charges, the dog was put down, sad story all around. It would be both fair and true to say it was more about small town vindictiveness than any actual harm the dog caused, but the owner refused to address the issues knowing the likely result and probably had no business owning such a dog.