If we don’t know why we are doing a project, then maybe we shouldn’t be doing it. But on many projects, if you ask the team “what will be different when we finish?” they look confused and start talking about the tasks they are performing.
But the tasks being performed should be moving toward some goal, which should be based on making something different to the way it is now (or would be without the project). Otherwise, to quote my grandmother:
How do you know you are not mistaking activity for progress?