The other day I watched someone unlock their car with a remote key. No big deal, a common occurrence. But for some reason I noticed it and thought that's cool. Maybe because I never had a remote key. I went from a regular, mechanical, non-electronic key, to a Prius with a "Smartkey" system.
With the Prius, I don't need to touch the key. I walk up to the locked car and open the door. As long as I have my key in my pocket or backpack it's all automatic. In other words, no user interface. (I'm now spoiled - I resent having to pull my office key-card out of my pocket, and even worse to have to use a mechanical key on my house.)
Too often in software (and other areas) we think the ultimate "solution" to a problem is some clever UI, like a remote key. But people don't want a clever UI, they want to get some job done, and often the less UI the better - none if possible.
Similarly, the best solution for errors is to prevent them in the first place. (again, no UI) You can't lock your key in the Prius because it won't let you lock the car if the key is inside.