The Tyranny of the Urgent
Picture a jar as representing your day. Then picture four golf balls representing the important things that you need to deal with that day.
Now consider a pile of beans
representing the many small-but-urgent details that interrupt your day and demand your attention. If you fill your jar with he beans, there is no room for the golf balls. However, if you first put in the golf balls, the beans easily fill the spaces that are left.