I found being really clear with myself about the things I was Not going to take care today was really valuable - it made it much easier to pull my focus back to what I was working on if I knew the other stuff was “scheduled” for another day.

Likewise, it's very freeing to completely rid yourself of a task mentally so that you can focus on the tasks at hand.

Part of it is trusting that future me can get it done properly. A trusting partner with which to delegate the task to.

That's a key lesson of Getting Things Done. Pick three tasks.