This post here.
Especially when someone comes into it from a Google translate page. You just know that they are on their last legs, searching for a desperate hope, and I am the best thing that the internet can throw at them. The LAST... BEST... AND ONLY!!! hope that exists to protect all of mankind from the scourge of ignorance!
What should I be telling them though? Use something other than Excel if you want to do complicated differential equations on the computer!