I didn't have a problem with it until I read your comment. Then I went back and re-tried it. Somehow, I just couldn't quite wrap my head around how to use it... Perhaps it's the act of me trying to "overthink" how to use the UI as opposed to just using it in what comes natural through innocent exploration.
The problem is that you have to think at all. It should be inherent and automatic for you to navigate where you want to go as a user. If you have to pause to figure out how to use the UI then the designers have failed.
