Printer predicament No. 3: The fallible human
Unfortunately, printers are physical, accessible objects. Users fiddle with them, load paper, change settings -- so they're automatically experts on the hardware, right?
A printer at a warehouse randomly goes out of whack, printing lines where they shouldn't be and skipping other lines where they should be. The IT pro and the foreman hatch a plan to catch the problem in action, which includes the IT pro racing 100 yards and up two flights of stairs to no avail.
Then they notice a worker go up to the printer and repeatedly press a button; a few seconds later the printer goes crazy again. When confronted, the worker explains how "pushing that button makes it print faster." Not even close, buddy.