I was in a funny in-between generation where I had a mix of GUIs and command lines first, through Atari/Amiga, and PC DOS and Windows (early 2.0, 3.x versions). The common thing about these machines were the unholy hacks one had to resort to to do more than one thing concurrently. The DOS TSRs or hooking things up to interrupt handlers on the Atari... heh. Anyway one day I watched someone type a command followed by an ampersand on some university Unix system. And again a few times. And they all actually executed concurrently, without any tricks like all but one got suspended. I still don't think I ever experienced the same feeling of awe as that day :)