Most modern dogs are companion dogs, and they may be rather spoiled as well. However, dogs were traditionally developed for a purpose other than accompanying owners to and fro. Many dogs were traditionally herding dogs, guardians, or hunting dogs. These traits became a part of a dog's personality, and, as breeders worked to emphasize those qualities in a dog, those traits became instinctual. As dogs have become companion animals, they often become mischievous if their humans don't allow them to participate in activities which mimic herding or hunting. To combat this, pet parents need to supply their working dogs with some activities that tap into that centuries-old instinct.
Small working dogs may often be cute companion dogs, but deep inside, they still need to work out their need for herding, driving, or retrieving. By playing games such as fetch, swimming or dock diving, or by allowing those herding dogs to put their humans into a destination pen, you can give your canine friend play time that allows them to follow their instinctive characteristics.