Socialisation from the beginning is vital, but it's also about how you treat your pets. Friends say that I am soft with my dogs and that I spoil them. I do no such thing: yes, I let them lick me; they sleep on the bed; they get treats: I don't smack them, and I don't yell at them; I don't leave them alone for long periods; they go almost everywhere with me; and we have fun playing together.
One of the problems with some owners of puppies is lack of consistency. Some of the things that puppies do they find amusing, but later they will chastise the dog for doing precisely the same thing. When a puppy does something wrong, no matter how funny, he needs to be disciplined so that he learns right from wrong. Discipline does not equate with punishment. My dogs have never been punished, but they have learned appropriate behaviour. It is too easy to laugh at a puppy's behaviour and do nothing about it, but as an older dog it is no longer a laughing matter. Unfortunately, the poor dog has never learned.