The first 80% in any project gets you close. That’s the easy 80%. That’s the part that makes you say, at the outset, “this shouldn’t be too hard”.
It’s the last 20% that takes 80% of your time and money, and causes 100% of the frustration. These are the decisions you deferred till later, the bits that looked small but complicated, and were convenient to avoid early on.
You might be tempted to call it good enough after the easy 80%, because at a glance you might believe that it is.
But it’s that last 20% that makes your product amazing, and gives your customers an experience that they’ll be eager to tell others about.
So maybe without that last 20%, the frustrating, back-breaking, sleep-depriving bit, maybe without that, it’s not worth shipping in the first place.