For the health and wellbeing of your dog, training should really not ever be considered an option when owning a dog. Well trained dogs are more likely to be behaved and listen, be void of behavioral issues, be good in public, and are less likely to bite. Owners also have a much closer connection with the dog when the time is taken to form a relationship through training.
Herding is one of oldest canine activities available. It has real world applications and is still in place for viable farm assistance in many places. For urban individuals, herding has become more of a training activity for competition for those breeds of dogs with natural instinct.
One of the kindest things any person can do is to adopt an animal from a shelter or humane society. These are animals that desperately need a home and human beings to love and care for them. However, if you have decided to adopt a dog from a rescue situation, you must go in with your eyes wide open.