Dogs have this rare combination of loyalty and fearlessness, which makes them great companions, especially if you are alone with her and happen to stumble upon a hungry bear in the woods. But those noble dog instincts translate to absolute retardation in the modern world sometimes. Dogs might win a fight with a bear in the wild through sheer bravery and aggression, but no dog has ever won a fight with a truck or a bus. Dogs just don't understand machinery or Newtonian physics that well.