migraine. Some dogs have even detected cancer or other medical problems in their owners. And then there is this dog who fetched help when her owner had a stroke. They can even make people feel better in the hospital.
Many dogs work for a living alongside their owners, herding cattle and guarding sheep. Many a rancher has stated that their working dog is invaluable to them, that they'd need to hire several more people to do all the jobs that their one working dog happily does. Then there are the people who participate in sports with their dogs, be it hunting, hiking, or jogging. There are even sports made especially for dogs like agility, obedience and rally.
We value our companion dogs for their loyalty, their trust, and their unselfishness. Many attributes that are hard for people to master come naturally to a dog. They don't judge people, don't care about your race or religion. They are forgiving and don't take offense. Our dogs love us despite all of our faults.
Dogs are so much more than man's best friend. They can teach us so much, as long as we are as open to listening as they are. (picture source)