Every part of a well-crafted artefact has been considered by its maker. Both on its own and as part of the whole. They are more likely to complement each other well, because of this thoughtful approach to each part.
This coherent approach means that the goals of the artefact can be served by every part of it.
It also means that each part of the artefact is likely to reward careful attention by its audience. Even the mundane parts may be interesting.