First jobs that most of us have involve manual labor and require little, if any, skill. These characteristics tend to go hand-in-hand of course. Without experience, there is no skill, and jobs that don't require any skill tend to be manual. My first paid jobs were mowing lawns and scrubbing pots and dishes. These are jobs that are quintessentially work and have no gradient of quality. The grass is cut, or it isn't. The pot is clean, or it isn't.
Nevertheless, these activities are useful to someone who will provide some immediate feedback. The homeowner will let you know if you missed a strip of grass, and a chef will really let you know if they pull out a half-cleaned saute pan.
But within a corporate environment among supposedly well educated professionals, this connection between work done and a customer experience is often lost. Even after moving up a few rungs, people can still be spend a lot of time on activities that may appear necessary but aren't clearly connected to an end product.
The problem that emerges from this disconnect is the inability to prioritize the work that directly benefits the customer and creates a positive feedback loop that can lead to even better products. The habituation of work done without direct benefit to the customer will lead ultimately to apathy towards the customer.
This can even happen while the team is ostensibly focused on the customer: we need to improve the design to enhance UX, we need to make sure we optimized the code for scale, and we need to have all the features that our customer would expect.
These are all truisms, but without a consumer of your product, none of them really matter. Often marginal improvements in design, UX, and performance are driven by the desire of those doing the work for the sake of the work, and not the benefit of the customer, because at some point in the past the work became more important than the purpose.
In business, thoughtfulness of design, aesthetic quality, and usefulness exist for the benefit of the customer, to improve their situation. Without the customer, they're irrelevant.