The Invisible Bug From Hell

Staring at this code for 3 hours wondering why your IDE can't find the ColorСhange() method? That's because some sadistic keyboard warrior snuck in a Cyrillic 'С' instead of a Latin 'C'. It's the coding equivalent of stepping on a LEGO at 2 AM while debugging. The worst part? It looks IDENTICAL until you're sobbing into your fourth energy drink trying to figure out why your perfectly valid code is "undefined" - and then you notice the microscopic font differences. Satan himself couldn't have designed a better torture device.