When does discoverability become a design problem rather than a design feature?

Last weekend I ran into a kitchen soap dispenser that completely stopped me in my tracks. At first glance it looked beautiful. Minimal, elegant, almost sculptural. But when I tried to use it, I couldn't immediately figure out how. There was no visible pump, no obvious interaction point, and no clear indication of where the soap came from. The solution turned out to be a small recessed button hidden on the side. It reminded me of a tension that seems to appear in many product categories. Designers often try