It's easy for you to take for granted just how accustomed you've become to a graphical user interface, but during the time this was something radical and alien to them. Once you've grown accustomed to it, its so EASY to take it for granted, but when something this radically new and innovative is introduced, it's hard for someone to wrap their heads around what exactly it is.
Well said. I think we all have to remember that a lot of commenters here are probably quite young and may find it just as difficult to comprehend a world before mouse-driven GUIs. I just dusted off my old C64 a few days ago to show my kids what sort of computer I grew up with, and it was quite a mental adjustment to go back to no mouse or GUI!