I wonder how many user interface features are pretty much subliminal. I was working on one particular interface feature and got stuck. To do it one way is pretty easy, but to do it another, better, way, is a lot more work. Then I was trying to write a little tweet about this to try to convey to my masses the difference between the two approaches, and realized that for the average user, the difference would be very subtle and they might never notice it unless it was carefully pointed out to them, and they might never really care on a conscious level. As a developer, I’d prefer to give them the better solution, but the difference is probably subliminal.
When I think about it, that’s true for a lot of software features. I’m sure it’s true in any design context.