How the post was shared out at the tax office

 This take dates back to the days of the Inland Revenue, before they became HMRC, when there were local offices each headed by a District Inspector (DI). 

One such DI went for a drink with his assistant to mark the DI's imminent retirement.

The Assistant DI took the opportunity to ask his boss to clarify something:

"It's always puzzled me how you were able to so often leave the office to play golf at 3 o'clock each day. 

In the mornings you always divided the incoming post into three piles. You and I took equal sized piles of post and left the third one for the next day. 

Even though you seemed to distribute the post randomly as between us, your desk was always clear at 3 o'clock whereas I often had to stay until 5 or 6 o'clock to clear all my post. 

How did you manage it?"

The District Inspector replied:

"Simple. When it got to 3 o'clock each day I put any answered post back on the pile that we'd left for the next day!"

Thanks to Richard Mannion who related this tale to me a while back. Not sure if he said it was a true story or a joke!