The quote from Jobs gets thrown around pretty heavily, but I also think it is interpreted very narrow sometimes. For me, "(...) how it works" isn't just about functionality, but about "how it works on the user". Yeah, aluminium plus glass may be a brittle combination, but if people like it, it just works. And this isn't on the same level as the "how it looks", because that can be quite different. Facebook Paper for example. It looks good, it "works" well (in functionality and purpose of the app), but it just doesn't work well on the user, because the concept is all wrong.