You assume people (and organisations) remain static
On the macro level—personalities change over time.
On the micro level—work personas are different to people at home, judgement alters when things are stressful or when certain situations arise.
This is fundamentally why a “fixed” project management just doesn’t work for making software. You set the requirements up front. People change in the interim. It comes out. At the very very best, it matches what was requested at the start. But it’s not what is wanted anymore. And people load in their own expectations, often not articulated, as they wait for The Thing and the reality never matches all of that.
Stop trying to engineer your way out of listening to people (via Hacker News)