The moment the demo became the product

There is a specific moment in vibecoding that nobody warns you about. The demo works. It does the thing. You show someone and they say wow.

Then they actually use it, and it falls apart in ways the demo never could.

The demo is a straight line. A real user is a curve with a detour and a wrong turn. They paste something unexpected, they click the thing twice, they leave the tab open for three days and come back. Your generated code handled the happy path beautifully and never met a real one.

I have started building every vibecoded thing with one rule. Build the demo, then immediately break it myself. Type garbage. Hit cancel. Reload halfway through. Whatever survives that is actually a product. Whatever doesn't was a very good screenshot.

How do you stress test something you built fast? And has a demo ever fooled you into thinking you were done?