To many readers, the answer seems an obvious “yes”. However, many people, too many, either can’t be bothered or don’t see dog training as important. Dogs, of course, vary immensely. Different breeds have their own instinctive behavior. Because of this innate variability, some dog owners do little in the way of training and yet have few problems, in the same way as some parents have an easy time when rearing an individual child. Just because your dog naturally behaves well, it is not necessarily a reflection of your skill.
The dog has very strong drives which can cause conflict. For instance, over a period of years one client of mine has had different generations of the same breed offspring of similar breeding lines. He used more or less the same approach to training each generation and yet had three different results. Chance obviously plays its part, so if you have tried hard but your dogs remains difficult, don’t look upon yourself as a failure.