Operator Error...

Those of us in the software business are very aware of the “operator error” problem – some behavior the user didn't expect, but which was actually caused by something the user unwittingly did.  With software, most of the time the real problem turns out to be a misleading or unobvious user interface design.  Some fraction of operator errors, though, are things you're never going to be able to fix by redesigning the user interface.  For example, if someone insists on putting their name into a field labeled “street address”, there's probably nothing you can do about it.

Toyota's notorious “sudden acceleration” problems turn out to be a case of operator error – users (overwhelmingly senior citizens) were stomping on the accelerator instead of the brake.  It's not obvious to me what one can do about such a thing...