Most responsible breeders have evaluated the temperament of each of their puppies before they are placed in a new home. A good breeder will know, due to hours of observation, which puppies are dominant and which are shy, which are energetic and which are easy going. Then the breeder will be able to match the puppy to the new owner and make sure that energetic pups go to active families and that shy puppies go to a home that can help them overcome their insecurity. This careful evaluation enables a breeder to choose which puppy will fit your household and much of the guesswork is taken out of the selection process. Good breeders can help you make an educated decision about all aspects of your puppy's feeding, training and overall maintenance and care based on your family situation.
Some pet shops make a big deal out of their puppies' pedigrees.
This is interesting, as the pedigree is really just a piece of paper with names on it. Unless you know the dogs behind those names the pedigree is really quite useless to the new owner. Most pet store employees do not know any more about your puppy's background than you do. A reputable breeder can tell you all of this information about your pup's family tree and more. When you buy a puppy from a reputable breeder you are getting more than a piece of paper, you are getting the important information associated with the names too.