Furballs can be gathered up to make life-size imaginary friends. Easy to leave clear signs about which new furniture you prefer.
Visitors know right away that there is a dog in the house.
Another excuse to rub hard, really hard, against that couch over and over and over. Fleas are confused by thick clumps of hair all over the house. Lose 10 pounds while not giving up any snacks or doing any exercise. Owner carries a little bit of you around all day. People who don't like dogs don't visit anymore.