Undone tasks hum in the back of your head. Finishing them is how you turn the volume down.

An unfinished thing keeps a small part of your attention permanently switched on. You are not actively thinking about the form, the message, the appointment, but something is holding the slot open, and it costs you all day. That hum is why a short list can leave you tired.

Write down everything that is open, then do the three that take under five minutes each. Book the appointment, send the reply, put the thing in the calendar. The quiet afterward is out of proportion to the effort, which is the whole point.