When you buy a pet-store puppy, you know nothing about the health or temperament of the parents. You have no connection to the breeder of the dog, no resource to go to if you have questions or problems a few months or years from now. But perhaps most important, when you buy a pet-store puppy, you contribute to the demand for puppy-mill-bred puppies, and add to the cycle of misery of mill-owned breeding dogs.