You cannot multi-task, it is a myth! You end up taking longer on both tasks verses staying focused on one task until completion, and then moving on to the next task.
You do not get back to maximum focus (or productivity) on a task for several minutes after being interrupted. Consequently, by switching back and forth between multiple tasks, you are actually working at a slower rate on all tasks verses maximizing your productivity on the most important task.
The key here, is the Most Important Task. Multi-taskers lose focus on the most important task and opt instead to make “some” progress on several tasks. This is the death of productivity.
Progress is not as valuable as completion. I do not know a manager that would not prefer to have one or two high-value tasks closed verses having a staff member make “some” progress on ten tasks. Especially when you consider that eight or nine of the tasks, by default, are not the most important and highest valued.