fire department analogy
I, for one, would love to see the look on firefighters' faces when they show up at a house only to see the homeowner folding laundry or alphabetizing books.
I'm pretty sure that in the grease fire analogy, there would be something else you could do ABOUT the grease fire. That would allow you to continue in the single-threaded mode. You may not put out the fire, but you could be corralling children, pets, or belongings away from danger; or clearing any furniture that may interfere with the firefighers' walkway; etc.
In other words, there may be actions to do if you are single-threaded and want to stay that way (for whatever reason). You don't need to Wait For anything.
On the other hand, if you want to be multi-threaded then, you would want to pick an item that can be done with little attention because your attention will likely still be partly diverted (due to the emotional investment).
In an abstract sense, you would like to be able to 100% drop your attention from Waiting For the firefighters and focus all of your attention on some new item, like Review script additions for latest sitcom pilot. In the real world, there are some distinct disadvantages to being able to drop and shift your focus THAT well. You don't want, for example, to get so absorbed that you don't notice the grease fire in the first place.