Communication is analogous to collecting liquid in a bottle with a funnel.
A good communicator starts with the big picture and gradually drills down to the details. A bad communicator directly starts with details that are obscure to their audience. When we start with the big picture, we are using the funnel’s broad inlet and gradually narrow down to the details. This way, all the information is finally to flow into a receiver’s head. When we start with the details, we have inverted the funnel. The narrow outlet barely collects any information, and the little that is collected scatters in spates to the sides of the bottle.
To communicate well is to streamline information in line with how our brains think – much like how a funnel streamlines the flow of liquid into a narrow bottle.