there's a very believable anecdote about an early p2p file sharing system, i think audiogalaxy -
"just downloaded an mp3, then see that the uploader is connected and getting the same file.
send a message asking why, replies "getting my song back, dick""
unfortunately, opening the door changes the temperature, so in practice instruments are calibrated from copies of the room built at other metrology institutions around the world.
adding to abnorc's excellent answer - circuit diagrams are all drawn as if charge carriers are positive (this is called "conventional current"), but because electrons are negative, this can get very confusing when you're dealing with components where the flow of charge is one-way only (diodes, transistors, batteries, photometers...)
A man says he's 6'6". Sure. If he's anywhere between 6'5½" and 6'6½", that's true.
You say he's 198.12cm tall. The range of this being true is now thinner than a needle. It has gone far beyond what anyone actually measures. In over 99% of cases, it's not true, and if it is, it won't be for long, because the human body isn't nearly that consistent from breath to breath.
The conversion with spurious false precision has made the number go from true to not true.
The man is six foot six, yes, true.
The man is 198.12cm - no he isn't.
When the original value is only precise to plus or minus half an inch, it makes no sense whatsoever to do a conversion that's a hundred times more precise.
It's the opening scene of "The Chase", TNG S06E20.
https://www.youtube.com/watch?v=SIRQF8PPvUU