I laughed out loud at this!
Well, it was a quick chortle, so I think it counts.
The main reason why looking at the invisible characters counts? Paranoia of being the Mac guy amongst Windows users when I was starting out, and before Unicode finally won out. Lots of Office copy-pasting colleagues meant secret formatting characters were resulting in mysterious failures, and I was the one who was able to find them. It left me a wee bit paranoid. 
