Your inbox is where your email arrives -- it's not where it is supposed to live. Some of those emails are well past their due date. Yet we still keep them in our inbox.
I can organize my desk while speaking with a client on the phone. I can skim through my email (and potentially even send out a quick response) during a conference call. I can make dinner while watching the news. In each of these cases, the quality of my work doesn't suffer. My efficiency doesn't suffer. And I get more accomplished.
Unlike animals, human beings have successfully developed the capacity to think about what is not immediately going on around them and to contemplate events that happened in the past or might possibly happen in the future. While this capacity called imagination can be a blessing, it can be a curse at the same time.