More a statement than a joke...
'Great job title',
I'll probably remember until I die, is 'sagger-maker's bottom-knocker'. Every year one of the English newspapers published a list of all occupations recognised by some trades council, and how many people were so occupied. For a couple of decades one of the rarest occupations was 'sagger-maker's bottom-knocker'--invariably
less than a dozen. Eventually, that occupation no longer showed up, so my father tried to find out what mysterious skill had vanished from the workforce.
As I understand it, a sagger is a large clay pot or box, used to store smaller items when the smaller items are being fired in a kiln. You fill the sagger, put it in the kiln, fill another, stack it on top of the first, and so on. The kilns can be thirty or forty feet tall inside, perhaps bigger, so you could have a stack of fifteen or twenty saggers. Obviously,
you have to be sure they're strong enough to handle weight on top of them.
A weak sagger at the bottom of a stack could mean the loss of twenty saggers' contents. How does the sagger-maker know his saggers are up to scratch? Once they're made and cooled he has someone tap the bottom to check by sound if the clay is consistent and solid. That person is a sagger-maker's bottom-knocker.
Now, at least as far as the trades council goes, a forgotten occupation. But wouldn't you love to say that at the pub when asked what you did for a living? "I'm a sagger-maker's bottom-knocker."