However, as will happen in even the most well regulated household, one day the owner is late. Well primed energies, ready for the greeting ceremony, demand an outlet as the adrenaline starts pumping. But it should. This introduces conflict between what it wants and expects and what is really happening. Conflict creates frustration.
Frustration produces anxiety, which triggers an even greater adrenaline rush.
It is rich with the owner's scent. If it cannot have the owner there, it can at least have their genuine odour or taste. So it sniffs, tastes, maybe even swallows parts of the article. Naturally, this does not fully substitute for the whole owner, so the puppy's social appetite is not really satisfied. Finally, here comes the owner.