Before you begin to build a house and break ground on the foundation you better have a blueprint and know exactly what you’re going to build. In physical construction, we really need to plan things out ahead of time to ensure that we have the right materials at hand and that things come together as we want them to.
This is a fundamental constraint of physical construction and it forces us to think about and construct physical things in certain ways. Virtual things do not have the same limitations and so in many cases, we can find more effective and efficient ways of constructing virtual things then if we were to just follow a similar plan that we would for constructing a physical thing.