Multi Tasking is a white elephant - unwanted and unnecessary. It's a corporate ploy to get us to do more whilst paying us less than our worth. Your employer is just trying to squeeze every drop of your life energy until you are a shrivelled like prune and then you're forced into retirement or have a nervous breakdown.
I know that from personal experience!
I've been told that multi-tasking at work is like doing the laundry whilst vacuuming. Now if I'd have wanted a job like that I'd have stayed at home in my domestic bubble!?? Then they tell you have to keep your plates spinning....well.....let's wait until they all come crashing down! Multi-tasking is just another way of keeping the busy corporate bods even busier....and interfering with the real workers - the ones who suffer in silence and give up their evenings / weekends to climb the ladder of "success".
If success is a state of mind then we can get off the ladder, stall in the rat race, revert to mono tasking and a life in the slow lane. This is when we are focused, calm and at our best - less is more!