In my upper level classes I talk a lot about aesthetic tension. It's a design tool, like repeat with variation, or unexpected proportions, that we can use to engage the viewer, or in this case the user. Aesthetic tension is when two competing or even contradictory aesthetics are in evidence. It is one of my favorite tricks to employ.
This mug gives us an example! The throwing lines are soft, but fresh; the decal image is crisp but degraded.