The task you're not doing is still costing you
David Allen's most useful idea has nothing to do with to-do lists — it's about what an unfinished commitment does to your attention even when you're not thinking about it.
David Allen calls it an open loop: any commitment your brain is still guarding because you haven't decided what it means or what to do next. The follow-up email. The vague ask from a teammate. None of these need finishing right now. They just need to stop being vague.
The mechanism behind it predates Allen's 2001 book by seven decades — Soviet psychologist Bluma Zeigarnik found in the 1920s that people remember unfinished tasks far better than finished ones, because the mind keeps a background process running on anything without a resolution. That's useful for a waiter juggling orders. It's a tax on everyone else, because working memory only holds a handful of items before performance degrades.
Allen's fix isn't heroic focus. It's cheap and almost insultingly simple: for each open loop, name the actual finished outcome, decide the very next physical action, and write both down somewhere you'll actually see them again. Not finish the task — just stop making your brain be the filing system for it.
The mind sweep doesn't feel like productivity. It feels like admitting how much you were already carrying.