Multitasking is Verbotten.

"Do not be desirous of having things done quickly. Do not look at small advantages. Desire to have things done quickly prevents their being done thoroughly. Looking at small advantages prevents great affairs from being accomplished."

- Confucius


Multitasking is Forbidden because it encourages slovenliness:

 
Confucius was right and he didn't even own a computer!  When we try to do too much all at once, we end up doing a poor job.  Poor work need to be revisited and done over again.  Where is all the time you saved dong several things at once?

Psychologists, neuroscientists and I are finding that multitasking creates stress and makes us less efficient.

Focus is sacrificed when shifting focus from one task to another in rapid succession. It gives the illusion of simultaneously tasking - Wrong! you are actually doing several things poorly.

We can do a couple of things at the same time if they are routine, but once they demand more cognitive process, the brain has hits a bottleneck.  Studies indicate that we can only focus on one or two items at a time with any  effectiveness.
 

Hall of Fame basketball player/coach John Wooden highlights the difference between work and honest to goodness getting stuff done: just because you're busy doesn't mean you're accomplishing anything.