I pay attention to people who work their dogs. These are the folks who put their terriers or dachshunds to ground, who shoot more than 200 rounds over their bird dogs a year, who put their running dogs out on hare and fox and coyote, or who herd sheep for a living.
And, of course, it includes folks who use guard dogs to protect their flocks because they live in an area where wolves, coyotes, lion, black bear, and grizzlies live in some abundance. Cat Urbigkit is one of those people, and she recently traveled around the world to look for better guard dogs for wool growers in the Intermountain West. She came back with Spanish Mastiffs. Compare and contrast with the non-working fantasy dog called the Neo! Another excellent post on the same topic on the same blog by Cat is Living with Livestock Guardians (Anatolians, Akbash, Aziats, Kangal, Karabash, Ovtcharka, and Great Pyrenees). Not much fantasy here!