Michael Wade explains the sidewalk rule and why we should build paths first.
Keeping things simple and action-oriented is difficult and yet if that orientation is not present from the start, it may be too late. Territory may already have been seized and boundaries drawn.

The Sidewalk Rule 
In a recent project, I took the advice of another team when setting up a new project and categorising the work involved based on a template this team used. In doing so, I complicated the project before it even began. I should have built paths first before building sidewalks.