Dogs, like humans, are extremely social animals and this similarity in their overall behavioral pattern accounts for their trainability, playfulness, and aptitude to fit into human households and social situations. This likeness has earned dogs a unique position in the kingdom of interspecies relationships. The faithfulness and devotion that dogs demonstrate as part of their usual instincts as pack animals closely mimics the human idea of love and friendship, leading many dog holders to view their pets as full-fledged family members. Conversely, dogs seem to view their human friends as members of their pack, and make few, if any, divisions between their owners and fellow dogs. Dogs fill a variety of roles in human society and are often skilled as working dogs. For dogs that do not have traditional jobs, a wide variety of dog sports provide the opportunity to exhibit their natural skills. In many countries, the most common and perhaps most important role of dogs is as companions. Dogs have lived with and with humans in so many roles that their loyalty has earned them the single sobriquet ‘Man's best friend.’ Conversely, some cultures regard as dogs to be unclean. In some cultures, certain types of dog may be used as food.