Here is an interesting article I found about the pitfalls of multi-tasking and the detrimental effect it can have on overall efficiency.

As a person who, partly through necessity (i.e. wearing too many hats!) is constantly multi-tasking I can avow to the fact that it does lead to inefficiencies and errors.  The challenge for me is - "Can I break the habit?"
Read more at...    What multi-tasking does to our brains

Footnote: The ultimate challenge to those Rotarian golfers is the trying to perform/remember the 500 things you have to do to master a perfect golf swing!  A classic case of multi-tasking to prove that we will never fully master golf!