Anyway, so making a good interface is very important, and can probably make or break a game.
I'm just wondering what the most annoying UI issue you have ever seen is. Like, counter intuitive controls or things that take ages to do. That kind of thing. Mostly this is just nitpicking! Unless you know of a really really bad problem, in which case I'd like to hear about it! :D
For me I don't think there is anything really major that springs to mind. I am annoyed at the latest Pokémon games for having animations for opening the Pokédex take ages. And you can't register screens like the aforementioned Pokédex. Also, uh, why a big fight button. Have all your moves on the same screen as the run, bag and Pokémon option. Tsk.
Ooh, also, Wind Waker HD. You can't use items by tapping them. You have to drag them to the button slot and then press that button.
Also, every game that doesn't let you customise your controls. I mean, really. Bonus points if they let you use a gamepad and don't let you customise that. Not everyone uses an XBox 360 controller, people!
I agree that UIs can break a game. Sadly, I tend to replay games instead of buying new ones, so I don't have any examples of bad UIs to offer. Sorry!
(Also, I haven't played any Pokemon game beyond Gen. V, so I can't comment on the UIs of the new games, either.)
I don't have anything to add, other than the fact that I clicked because I suspected this thread might be about urinary infections. If it had been, I'd have more to say, perhaps.