What's crazy to me is that 25+ million people on this Earth can program, and how many of them get to decide the UIs that everyone else uses? I myself, suck at UI programming. But that's because UI programming is labyrinthine, arcane, and generally requires becoming an expert in a number of extremely poorly thought-out frameworks that are often stupendously complicated. (Web, I am looking at you.)
Why can't I rip apart the UI of an app I use every day and rearrange it the way I want? And I mean, far more than toolbars and rearranging drop down menus. (BTW, remember those? Those were great).
Seriously though, I have written many hundreds of thousands of lines of code in my day; I fancy myself not super bad at programming, yet I cannot take apart a random GUI app and make it do what I want. Even when it's open source. I feel like this is an unaddressed problem; the UI cafeteria people keep serving us an ever-changing menu of crap, and I feel powerless to even lock in the few UIs that I do end up getting good at. They'll take that away soon enough.