Multi-tasking can work, depending on the tasks, but, in my experience, can cause work to come to a screaming [by me] halt. Then I need to reconsider and reprioritize.

ONE THING

One thing at a time--
Cause for reason and for rhyme--
Calls for order and for pace,
Calls for discipline and grace,
Calls for time to get it right,
Calls for making choices
Calls for sticking to a list
Calls go unanswered and they bring
Order with joy and each such thing--
One thing at a time.

Complete the task now at hand
And you will feel forever grand;
Relief and joy and rest will follow
And you won't feel that kind of hollow
That comes from all directions and none
Complete one thing--do it till it's done.