What do you when you suddenly think of an action that you should do, but it's not the next action. Perhaps it's the action about 2 or 3 actions down the line and it doesn't make sense to do it as a next action (eg. it depends on the completion of an actual NA). For example, you're concentrating on an action you're doing and it's going great, and then you think "hey, I after I do this thing and the next thing, I could do X". What do you do with that idea? The NAs lists only contain the next action, and the projects list is supposed to be just a list of projects or outcomes.
Perhaps each project should have a little list of actions next to it, and the NA list should just show the very next one? I find that I'm not sure where to file these ideas as they pop up, and they therefore tend to hang around in my 'ram', cluttering my mind and leaving me quite definitely without a mind like water!
BTW, I'm a programmer, generally working on projects that have no 'right' answer - the answer has to be created by me and therefore it's quite a creative sort of thing to do. So there's lots of ideas about how things might be done coming into my mind all the time. The ideas don't require me to be in a particular context for me to think about them, so sometimes I'm "working" 24 hours a day, as I can progress projects anywhere. This is good because I can work anywhere, but bad because there's stuff in my ram 24/7 and when I want to file it and forget it, I don't know where it should go so it stays in my ram.