1) Would always miss when he clicked (single click). He'd line it up, eyebrows screwed up in concentration, raise his index finger up high, bit his tongue with intensity, and mash that finger downward. Unfortunately, all the full-body effort of mashing that finger down meant that he skewed the mouse a good few centimeters in a random direction, meaning the entire task started over again.
2) Absolutely did not understand that Wordstar (yeah, you read right) isn't a typewriter. He would laboriously space-space-space-space... manually center text. Hit enter at the end of every line. He would type sentences in -- while staring at the keyboard and using his index fingers -- only to finally glance up and notice an error three lines prior. He would then backspace-backspace-backspace... deleting all the characters until he reached the offending error.
Watching over his shoulder provided perhaps the most fascinating and educational experience I've ever had in user interfaces.