The moment you pick up your new puppy you are beginning to form a relationship that will be the basis of your life together. The bedrock of that relationship is respect, affection for each other and understanding leadership from you. Your pup may become your companion, friend and member of the family but it will always be a dog and although we may anthropomorphise with our pets we must always recognize that very important fact - it is a dog.
Your pup is learning and being trained every minute of the day even when you are not formally 'training'. Habits and behavior patterns are being formed all the time and these first months of ownership are the formative ones. Lessons taught now will last a lifetime. It is easy for pup to learn good habits if we think about what we are doing but so often we owners teach bad habits without even realizing.
For example, owners and visitors often encourage a pup to jump up to be petted and think it is so cute. They rub, pat and pet its head vigorously, tease it with an old sock or special toy, and play tug of war. They grab and catch it as it is running away or even coming towards them. They often wake up the pup when it is not necessary so that they can enjoy snuggling and petting it. Would you do that with a young baby? If the young pup has an accident and urinates indoors (usually because an owner has not been watching closely enough or doing 'puppy management' correctly), often they shout at it, chase it down and take it outside telling it what a bad dog it has been in a very stern voice. They may even rub its nose in the urine to 'show it' what a bad pup it has been and 'teach it a lesson', thinking someone somewhere said that was the thing to do. As pup grows up and 'learns' from these experiences it knows people enjoy them jumping up, that hands grab when you don't want them to, that humans disturb and irritate you when you are not in the mood, and it learns that hands and people sometimes must be avoided or warned off. It also learns that it is not pleasant to urinate when people are around (even in the yard!) or if you do hide so they cannot see you doing it.
These are just a few examples of how a pup learns and is taught the wrong behavior without owners even realizing. Most owners want four basic things from their dogs. Firstly to be clean in the house, secondly to come every time they are called, thirdly to walk nicely on a leash and fourthly to have good house manners such as greet guests nicely and chill out when required.
For some reason dog training is considered something that every owner can do. The dog will learn as it grows or in many cases the owner claims it will grow out of the bad habits it learns. Not so. The dog will learn and keep a behavior that you develop. Some of its behavior will come from natural instincts and inherited behavior but there is no doubt that what the owner does during the first four weeks of ownership shapes and builds permanent behavior.