On the question of dogs: different breeds were originally bred for different puposes with different characteristics being developed.

Labradors were bred as retrievers. Which is why the breed have a "soft mouth" - there aren't many dogs that can carry an egg in their mouth without breaking it. or our one's party trick: to carry his dinner bowl in at dinner time.

German shepherds were bred as sheepdogs. hence they tend to be more intelligent than some dogs and to be 'one man dogs' - so they respect and obey the shepherd.

Bulldogs were bred for one form of bull baiting - they would bite the bull and hang on - hence the shape of their mouths.

Bull terriers were bred for bull baiting. Hence their quick reactions.

Pit bull [terriers] were developed from the more aggressive bull terriers as fighting dogs. They were bred to be aggressive.

I could go on boring you with the characteristics of other breeds but I think the point is clear. A dog is bred to have certain characteristics that mean it can be trained as a working dog. If trained otherwise or not trained, it's basic nature will come out.

Sadly, this is what has happened with pit bulls, rottweillers, dobermans , german shepherds etc. They have been trained as fighters or guard dogs. But being dogs, they cannot differentiate between one perceived threat and another so they attack. And those who don't understand a dog's nature call it an "unprovoked attack"