Animals do this physically. A dog that's had a fright shakes itself out, head to tail, then goes back to sniffing the grass. The event is closed and the body has been told.
People skip that part.
The day comes upstairs with us instead — the meeting, the tone of a message, the sum that didn't work — and circulates all night with nowhere to go.
Something crude usually helps. A walk to the end of the road. Ten minutes of music with the volume genuinely up. Changing out of the clothes you wore all day. Not to solve anything, just to tell the body the day is over.