The idea of setting the bar for your dog isn't on the mind of most pet owners. They are quite content with their dog cuddling with them after a stressful day. As a trainer, thoughts of catching issues before they develop has crossed my mind on several stubborn dogs I've worked with. If only I was there when the dog was a pup to shape and develop good behavior.
A good example of shaping and developing in puppies are at about 4-12 weeks when their fear response begins to emerge. Exposure to everyday items like shoes, keys, chairs, vacuums, toys can help desensitise fear in the future. Exposure to as much things as possible helps develop a well rounded and stable dog that isn't fearful as age goes on. At this time starting puppy manners are essential to develop to stop jumping, unnecessary, barking, housebreaking, and even kennel training to teach independence and calmness. Socializing puppies to people, other animals, high traffic, different surfacing, and water.
The next stage in a puppy life stage is the most important stage for learning, teaching, mental growth. This stage is at 3-6 months when obedience training is perfect time, and learning new things like agility, scent work, and other sports. At this stage pups are more willing to please you and want to do things with huemans around them. Some people want Puppies from breeders vs. shelters for these reasons which I don't blame them for.
Behavioral issues can be prevented at an early stage with proper guidance to shape and develop the pups growth. I have spoken with people who say that they were told that training and structure should be given later in the dog years when the dog is mature and able to handle obedience commands. That is the most silliest thing I've heard. By doing so you leave out a lot of very important skills and form bad behavior that can feel almost impossible to correct which can lead a dog to a shelter for its remaining life. As a trainer my goal is to not just train your dog but help your dog never go to a shelter and stay in your home.