Intuitive User Interface

When developers think they've achieved UX perfection by making something "simple and intuitive," but users somehow find a way to use it in the most spectacularly wrong manner possible. That teapot has a perfectly functional spout, yet here we are watching tea arc through the air like some kind of caffeinated fountain.

The gap between developer intent and user behavior is wider than the Pacific Ocean. You can spend weeks perfecting the user flow, adding tooltips, writing documentation, and conducting usability tests... only to watch users confidently ignore every design decision you made and create their own chaos.

Pro tip: If you ever want to test your UI, don't give it to other developers. Give it to your non-technical relatives and prepare for your soul to leave your body.