I love pets,dogs ,cats etc .pet or companion animal is an animal kept primarily for a person's company, protection, or entertainment rather than as a working animal, 
What's your favorite pet?
The domestic dog, the most widely abundant terrestrial carnivore
Why are they human friendly hence the use of pets?
Pets can give companionship to elderly adults who do not have adequate social interaction with other people
What other notable stuff do they do?
such as children in hospitals or elders in nursing homes. Pet therapy utilizes trained animals and handlers to achieve specific physical, social, cognitive or emotional goals with patients.
Some scholars, ethicists and animal rights organizations have raised concerns over keeping pets because of the lack of autonomy and objectification of nonhuman animals.
Pet popularity.
There are approximately 86.4 million pet cats and approximately 78.2 million pet dogs in the United States, and a United States 2007–2008 survey showed that dog-owning households outnumbered those owning cats, but
Pet
A pet or companion animal is an animal kept primarily for a person's company, entertainment, or as an act of compassion such as taking in and protecting a hungry stray cat, rather than as a working animal, livestock, or laboratory animal. Popular pets are often noted for their attractive appearances, intelligence, and relatable personalities, or may just be accepted as they are because they need a home.
Two of the most popular pets are dogs and cats. The technical term for a cat lover is