The conveyor belts are running but nothing is being processed

Imagine a delivery and processing department. Now imagine many conveyor belts and robotic couriers collecting and distributing information to numerous, apparently vacant offices spread over many floors. Everything is running efficiently, gently purring away.
Now imagine a lone package.
It enters the hall and like expectant fathers, the robots and belts twitch with anticipation, will they be firing at full capacity once more? What is coming?
Imagine the sadness when the lone package, efficiently filed, is all there is.
Forgotten, the robots go back into standby mode once more.
This is how my brain feels now retirement has come and this is why it is so important we all, in retirement,  stay mentally active.
We have these efficiently operating brains which need to keep working.
And if we don't?
The dust, the decay, the lack of maintenance starts to take its toll on the robots. Updates are no longer made. Conveyors of information fall idle and lose their connections, failing to notice an old colleague has died and been replaced or their position left vacant.
Like any processing department,  once it's no longer in use, those who operated the various positions are made redundant, the departments are mothballed and the doors padlocked shut, and we know what happens to places like this don't we?