Yes, I've heard of PICNIC too. But let's not speak of "stupid" users, please, because most users will have brain farts from time to time (or will be uninformed). It's the stubborn users (i.e. the ones that insist they are right, or who keep doing the wrong thing despite being told that it's wrong) who cause the biggest issues.
Other error codes include:
- Layer 8 Issue: A reference to the OSI model, implying the human layer (above the 7 standard network layers) is at fault.
- Code 18: Indicates the problem is 18 inches away from the screen.
- IBM: Idiot Behind Machine.
- "Magic smoke": The stuff that makes all electronic appliances work. When it escapes, they stop working.
But don't use these while talking to a user (or your boss), or it might become a CLE -- Career-Limiting Event.
And so to you, I say "HAND!" (Have A Nice Day)