That reminds me of Stephen Hawking's computer. His old computer gave deterministic dictionary predictions and after some time, he had memorized all the predictions that came up, so he could be much quicker because he knew exactly how much of the word to type and then to select the proper word - a purely mechanical process that doesn't require feedback anymore. However, when they gave him a new computer, it had adaptive predictions (I think) and Hawkins could not memorize them anymore. Then he always had to type letter for letter and inspect the predictions before he could select one - a huge step down.
Stuff like that is absolutely crucial but is often forgotten by engineers.
Seconded, and yet it's madness to me that engineers don't pick up on this. I can't be the only one who's let someone use my computer for basic internet browsing and then been deeply irritated when their newly visited sites break my intuitive knowledge of how many characters I need to type in the URL bar before hitting enter...
Stuff like that is absolutely crucial but is often forgotten by engineers.