As a creative it is easy to get lost in details...
In traditional painting practices of ateliers they are constantly reminded to step back and squint - look for the masses and abstract shapes, look at the bigger picture.
This is emphasized to avoid the effect inexperience has in making us focus on what is right in front of us.
If you do not know about what you are doing you cannot prioritize and fall into a sequential and fickle process, dabbing at the detail of your attention, beating a piece of dead meat and ultimately going nowhere.
You forget the important for the urgent.
The same quality of expertise can be seen in software development. Novices will write code in an ad-hoc way, impromptu and unplanned - whereas masters will carefully design, plan and only then execute their actions.
It is not necessarily that the ad-hoc way of doing things is a bad practice - it's just that the best practice of considering the design, the bigger picture is much more effective in the long term and in fact ends up taking much less time...
By getting lost in the details and implementation of what we want to do we often loose sight and forget about the WHY of the whole thing. If you forget that then you have no compass, no map, no direction, no value heuristic that'll help you in making decisions.
You want to make the decision process as easy as possible. You do that by having a clear definition of your aim, to separate the good choices from the great.
By having a well drafted map you will navigate the labyrinth of minutiae with ease, remember that next time you get lost.