User interfaces matter. I was watching a recent episode of The Taste, and one of the contestants' meatloaf just wasn’t cooking. Every time she went back to her oven she’d see the touch screen display 350F. She would slide the touch-based temperature slider to 550F and walk away. But when she’d return, the temperature was back to 350F.
The first time she did this I had a suspicion. The second time she went to back to the screen, I was able to confirm it. The temperature selection screen had an OK button on the bottom right. Just like it’s a modal dialog. She would set the temperature, but walk away without tapping that all-important OK button so the temperature wasn’t actually being adjusted.
User interfaces use metaphors in order to access shortcuts you already have in your brain. This is why skeumorphism is used in the design of digital interfaces, so you don’t have to learn a completely new way to perform a task.
One of the most simple interfaces is a lever. It affords manipulation and it augments human capability: you can exert greater force. But it’s also a metaphor for what a user interface is. If an interfaces does not enable enhancement of capacity, it is actively a hinderance. To avoid cargo cult design always consider what you attempting to enable and how much leverage you are contributing.