Yes its great to be in flow state where everything is peachy. But people who have tried to build something know that you will constantly bang your head against different walls that need effort and solving. And you dont know how much effort is required until the task is done.

When you are cheerfully and methodically banging your head against walls, the solutions come more fluidly than when you are in a rush.

And the more furious you are about wall proliferation more likely head banging will result in unwanted consequences.