You Put The Disk In Upside-Down

Jordan Mechner on his game Katateka:

The programmer doing copy protection for the game figured out that by messing with the bit table, the whole game could be played upside down, which is really hard to do... We thought it would be hilarious if we burned the flipped version of the game to the other side of the disk. We figured of all the people who buy the game, a couple would accidentally put the floppy in upside-down. That way, when that person called tech support, that tech support rep would once in a blue moon have the sublime joy of saying, "Well sir, you put the disk in upside-down," and that person would think for the rest of their life that's how software works.

Gold. Solid gold.