The busier you are the more difficult it is to provide detailed and in-depth communications on your thoughts. Not having time makes it difficult to communicate completely clearly. By default you must now open yourself up for interpretation and miscommunication. This means your going to get responses back that you don’t expect – both in tone and requests for clarification.
Taking the time to get people back on the same page as you can be frustrating. Calming those that took what you said the wrong way, reexplaining yourself to someone who didn’t grasp what you were originally asking for, or just following up because you didn’t clearly articulate an action. You’ll often end up with taking more time to get it done than just taking the additional time up front.
Why do we always assume we need to do this by email? Sometimes just picking up the phone better emphasizes the importance of the task, gives you the opportunity for immediate clarification and speeds up the process tremendously.