The paradox here is that the most effective UI would be one where you'd have minimal "signs" (text or otherwise) telling you what to do. The problem with this i

The paradox here is that the most effective UI would be one where you'd have minimal "signs" (text or otherwise) telling you what to do. The problem with this is that you'd have to _learn_ how to master it. What we have is a compromise. Something that tries to cater both to casual as well as power users. I'm thinking about for example a swipe based touch interface. A lot of functions now are click here, then click there, when they could be done in a simple gesture. But the problem is that one would have to learn the gesture somehow in the first place. And people don't read manuals, even if there were any nowadays.