Tech support proud moment: in the 1990s, walking a non-technical user through editing and then saving a config file for the product I was supporting, with him using vi and not being familiar with how it works, over the phone. The vi editor is the one that you know is always installed on every Unix system.
about 2000, my father called me one day while i was somewhere in middle of mountain.. about something going wrong, entering the BIOS-setup of his machine... and in the next 15 minutes i had to recall and imagine all them 6-7 screens of BIOS of his computer, and lead-him-"by-hand", that is, key-by-key... Luckily i had same BIOS on my machine so it was been.. familiar. While even if he was seeing all the text there, it meant nothing to him...
