The world of dogs as seen from a dog lovers perspective.

The world of dog involved people can be divided into two basic groups. The dog owners of this world and the breeders who supply those dog owners.
Dog owners can further be divided up as follows:- Those who want dogs as companions or family pets, those who want a dog to protect them as watchdogs and those who want the dog to assist them in some way. This could be anything from guide dogs for the blind, to therapy dogs, to drug sniffing dogs and hunting dogs.
Of those who want to have a dog as a pet, about 1/3 rd of them will buy a dog from a registered breeder. The rest will get them from a hoard of different places. For instance pet owners who have not had their bitch spayed, she comes into season and is covered by the local neighbourhood dogs, a litter is born and given away or sold. Others are obtained from rescue shelters etc. Of those buying from a breeder only a very small number will ever want to show their dog, the registration papers that you will get from the breeder are mostly just for bragging rights.
One thing to keep in mind is that you will more than likely be getting a dog with less potential health problems if you get a mixed breed, than you will buying a highly pedigreed dog.
Getting a dog as a working dog requires a very different approach, most of the purposes that working dogs are put to require a serious amount of training, for instance a guide dog for the blind is trained for years, and from a reasonably young age, to carry out this very exacting task. So too are dogs like tracking dogs, and drug dogs as well as hunting dogs and herding dogs. All or almost all of these dogs will be bred and trained by the breeder or sometimes even the society (like the blind dog society) for their specific tasks. This means that in these circumstances you would be buying an adult dog.
Next we have the breeders; they can also be divided up into groups. There are breeders who believe it or not do not even really like dogs. To them this is just a business; these are the people that run puppy farms. Be very careful of these people when looking for a puppy for yourself, avoid them like the plague. They normally have a number of different breeds together at the same kennel, and they churn out puppies like it’s a production line.
The next type of breeder is slightly more ethical, but not a lot more humane. They breed only one breed of dog, and these dogs are show dogs. To them, selling their puppies are secondary to the show standard being attained in their breeding (they are not stupid, so they realize that they have to sell puppies to carry the cost of their showing aspirations). These breeders will routinely kill little new born pups because these poor little animals don't meet their desired standards. I have personally seen a breeder drown a litter of pups because they had kinks in their tails, can you believe it! My personal belief about this type of breeder is that they have a god complex, not necessarily bad, just trying to compensate for some unknown inadequacies in their makeup.

The next type of breeder is the one that I would recommend going to if you want to buy a pup. These people love the dogs that they are breeding, they are honest and conscientious, they will make sure that the breeding stock that they use is free of inherited diseases (like hip dysplasia in bigger breeds). When they have a litter that does not conform to the required standard, they will either sell the pups as pets rather than as show dogs, (these will not be registered by the breeder, so don’t expect papers) or they will just give them away as pets.
Last of course is the specialist breeder, breeding for work purposes. As I said earlier these folks handle the whole package, but you will often find that they too have dogs that have not met their specialist training requirements, and these dogs are normally sold as pets. This does not mean that there is anything wrong with them, just that were "washed out of the course”. They will more than likely still make lovely pets.