Neal Stephenson has a funny anecdote about explaining PowerPoint to a friend of his who had managed to be unaware of it until now, culminating in Stephenson's explanation "for people who can't communicate, it's what a dialysis machine is for people who don't have kidneys" [1].
This is the culmination of his response [2] to a question [3] in the Q&A period of a talk on his book tour for Seveneves [4]