I don't understand why "shut up and show me the code" isn't the right response to a UI discussion. At the end of the day, user interfaces aren't some magical thing that only experts can fathom. They're just like any other engineering problem.
Unfortunately, there's a strong "popularity contest" aspect to user interfaces. We use QWERTY because QWERTY is familiar. QWERTY is familiar because we use QWERTY. etc. Similarly, a lot of arbitrary choices were made back in the last 20 years (close box on the right of the window, etc). Well-meaning engineers who create "unconventional" user interfaces find that most people are allergic to them, simply because they're unfamilar. (Case study: GNOME3.)
Another aspect is that UIs are targeted at different types of users. emacs and vi are great user interfaces-- for programmers. Not necessarily for non-programmers. Failure to design something with the needs of its intended audience in mind is another leading cause of UX failure.
None of this stuff means that UI design is some sooper secret thing that non-designers can't possibly comprehend. Just know your audience, and stick to the familiar whenever possible, and you'll be most of the way there.