According to Don Norman, a product is not only a product. In reality, a product is a service.
The most important factor of a product is the experience. If a product is a service and if the experience with that service is a negative one, the product itself will be perceived by the user as bad product. A good product allows the user to enjoy its service through a good experience.
In this case, the experience is not necessarily just the interaction, but it's constituted by several phases, such as: discovery, purchase, anticipation, opening the packaging, updating, maintenance, exchange…
A product or service is the culmination of a relationship of different stages that will originate it. If all these steps (areas) interact fluently with each other, the better the quality of the service (product) will be obtained. That is why it is necessary to see this process as a system and not just as simply as a product.

“No product is an island. A product is more than the product. It is a cohesive, integrated set of experiences. Think through all of the stages of a product or service--from initial intentions through final reflections, from first usage to help, service, and maintenance. Make them all work together seamlessly. That's systems thinking.”
Don Norman
Sources:
[1] - Systems Thinking: A Product Is More Than the Product by Don Norman