I have sometimes wondered whether our unconscious motive for doing so much useless work is to show that if we cannot make things work properly we can at least make them presentable.
"A builder who hides any part of the building frame, abandons the only permissible and, at the same time, the most beautiful embellishment of architecture. The one that hides a loadbearing column makes an error. The one who builds a false column commits a crime."
Contemporary architects are, however, increasingly engaging with ornamentation. The zenith was Grayson Perry and Charles Holland of FAT’s fairytale House for Essex (p64), but it does not serve as an indicator because the involvement of an artist has allowed an enhanced engagement with ornament until it surpasses mere decoration and becomes embodied in the architecture in a way that architects do not allow themselves to do. Think of FAT’s old work: the ornament is all contained within a surface - a facade - which allowed them to separate out the (Modernist) architecture from the (kitsch) superficiality of the elevation. Like Venturi before them, their ornament allowed them to have their ornamentally iced cake - and eat the Minimal Modernist sponge underneath.
Perceptual: "They couldn't figure out what to do next", "they couldn't find the feature", "they didn't know they could click that button..." etc.
Domain-specific: "We need a way to jump back here because in their workflow this happens..."
In general, usability testing only catches type 1 perceptual problems. Because in those tests you take people out of the real world and assign them tasks. Usability testing doesn't catch domain-specific problems because they only come up in real life use.