The demo-to-production gap
The distance between 'it works in the demo' and 'it works in production' is where most of the real engineering lives.
A demo is a happy path with clean inputs and a forgiving audience. Production is messy inputs, real volume, edge cases, failures, and users doing things you never imagined. The gap between the two is wide, and it's exactly where the hard, unglamorous work lives.
Demos hide the hard 80%
It's why an AI feature or automation can look done in a demo and be nowhere near ready. The demo skips error handling, scale, security, the weird data, the recovery when something fails. Those aren't polish; they're the majority of what makes something dependable.
Budget for the gap
The mistake is treating the demo as 90% done when it's more like 20%. Plan for the production-hardening work explicitly — the validation, the failure modes, the load — because that's where the timeline actually goes. A demo proves it can work; production proves it does.
A demo shows it can work once. Production is the work of making it work every time.