Prototypes are great. They let the user see and feel what the final product will look like, either in printed or in online form.
They suck when the customer wants it next week because “it’s just a bit of wiring up to get it working”
And they can be dangerous. Ship that button without properly tested, or incomplete, code behind it and your software could crash and sink without trace.
If you want to always be finished, you need everything that the user can interact with to meet your quality standards. No unguarded exceptions, no raw data, no untested code. And if that means leaving that button out until it’s ready, do it. Or put in a bulletproof, well tested placeholder, like an email subscription to find your beta testers.
The user doesn’t know or care about all the mass under the surface that they can’t see, so don’t expose them to it. Keep the interface clean, simple and error free. Build up behind the scenes, behind feature toggles, and off production until you’re sure it’s safe.
The one thing worse than a missing feature is a horribly broken one. A user missing a feature may come back when the feature is ready. A user who’s experienced a broken feature won’t come back until they trust it.
Don’t lose your users’ trust.