It's not just simple UIs, though -- As a programmer, I generally need to be able to dig down through the code and figure out what's going on behind the scenes.

It's not just simple UIs, though -- As a programmer, I generally need to be able to dig down through the code and figure out what's going on behind the scenes. This means that the implementation is often just as much the UI as any other aspect of the program. Simple implementations are just as important as simple UIs.