It can be most difficult to deal with this type of owner. On a purely logical basis, the owner thinks something must be done to change the dog to fit the treatment rather than vice versa. Most often the emotional relationship between such owenrs and their dogs is either absent or shallow. Then it is usually up to a behaviorist to discover the threads of some emotional bond and then stimulate the owner to develop that relationship and gain the motivation necessary to salvage what is usualy a worthwhile dog from a difficult situation. These are but a few From a breeder's point of view, we are not Gods, fortune tellers, nor whipping posts.
Good breeders sell what they believe to be good solid well tempered puppies.
Things can go wrong but many extremely knowledgeable dog behaviorists have stated that most problems are created through ignorance and environment than are ever born. If you have a problem with a puppy or older dog, instead of looking to lay blame, look for a solution before irreparable damage is done.