Next Actions: Don't Get Caught In the Nonsense
Where Getting Things Done's "next physical action" idea really becomes useful is in the things you're stuck on.
If you make coffee as part of your morning routine, that doesn't mean you need to put "spoon grounds into filter" on your next actions list--you know how to make coffee. You know how to do lots of things, maybe even some very complicated things, in your personal and work life--the object of all this stuff is not to overwhelm you with hypergranulizing everything you do.
But if there's something that's been stuck on your to-do list for days, or maybe weeks or months? Poke at it. Why haven't you done it yet? Is there some dependency hidden inside of "- replace broken coffee maker" that you haven't thought about, or that you're avoiding thinking about out of some kind of anxiety or fear?
Have you not bought the new coffeemaker because if you pick one without your SO's input you're gonna start an argument, cause one time a Keurig made him some really bad coffee? Or is it just that you haven't comparison shopped on Amazon yet? Maybe your next action for "replace broken coffeemaker" is "talk to SO about what kind of coffeemaker they want." Or maybe it's "look into Keurigs on Amazon." (Don't get a Keurig.)
But the point is--next actions are about breaking big nouns into useful verbs to move you forward. Don't get caught up in the nonsense of crossing things off your list that might not even need to be there to begin with.