Treating your to-do list as only being for “urgent” things, and you avoid writing down anything else, is probably how you got in this situation in the first place. If you made sure to write down and plan for all things, even the “non-urgent”, then your mind would probably be calmer. Speaking from experience here, but this is also what David Allen (who you refer to later) talks about. I think you are missing a key point in “Capture” — it’s about capturing everything, not just what you think is worthwhile. Tasks and commitments take up mental space just the same even if you don’t think they’re important.