Google Glass

Google Glass worked. The display lit up, the camera shot, the voice commands responded, and early adopters lined up to pay around $1,500. Then they wore it into the world, and the device that performed flawlessly on a spec sheet turned its owner into a social problem. Bars banned it. A wearer was assaulted. A new insult entered the language. The hardware was never the issue.

This is a product case about the gap between 'does it work?' and 'will people use it here?' It sharpens how you evaluate adoption when a product imposes social, professional, or behavioral costs that no feature can pay down. Where the same hardware later found real traction, and the question you should ask before 'does this work?', is what the app draws out.