The Peter Principle states that in a hierarchy, individuals are periodically promoted as long as they continue to perform adequately. When they stop, they are said to have risen to their level of incompetence.
A corollary for multitasking: an individual performing all their tasks adequately will add tasks until they can no longer do any of them well. This miserable state is called being "busy".
At this point I could pontificate about quiet, but I'll just say this: busy kills. Hang up and drive, folks.