The science of the building trades is frequently more than mere mortals can comprehend. A few moments in the building supply store, for example, will unveil a stream of such jargon and other obscure references that it's often difficult to see how anything gets built. Once in a while, this obscurity finds its way to the job site as well.
Not long ago two fellows were working a construction job at a new house. The younger of the two, a man anxious to impress all around him with his skill and dedication, was nailing down siding. He would reach into his nail pouch, pull out a nail, and then either toss it over his shoulder or nail it into the siding.
The second, an elder esteemed for his deep knowledge of building mysteries (at least in his own mind), saw him tossing all the nails over his shoulder and asked,
"Why are you throwing those nails away?"
The first said,
"If I pull a nail out of my pouch and it's pointed towards me, I throw it away 'cause it's defective. If it's pointed toward the house, then I nail it into the siding."
The elder was outraged at the younger man's ignorance and waste.
"Idiot," he yelled. "The nails pointed towards you aren't defective; they're for the other side of the house ..."
---------------A Final Thought ...
"Believe me, that was a happy age, before the days of architects, before the days of builders."
- Seneca (c. 5 BC–AD c. 65), Roman philosopher, statesman