In the late 1700s, Thomas Jefferson wanted the United States to adopt a unified system of measurement and saw the metric system as the best solution. However, a pirate attack in the Caribbean disrupted these plans. Joseph Dombey, a French scientist carrying a kilogram and meter stick to demonstrate the metric system, was captured by pirates. By the time France sent another scientist to explain the system to the Americans, Jefferson was no longer in office, and plans to go metric were disregarded.
NASA still almost lost the Mars Climate Orbiter in '98- they used metric, and Lockheed used US customary. Probably put it on approach too close to mars, and uh, it “encountered” the planet…
NASA has the best euphemisms.
(edit: also in 3d printing world…we almost always use metric, partly because it’s literally an international community.)
One thing I find humourous is the term ‘US Customary’ - I’ve only come across it recently; to most of the world they’re Imperial units, which is ironic given the nature of how the USA came about.
Strictly speaking, there are a few places where Imperial measurements diverge from US customary measurements; the sizes of a fluid ounce, pint and gallon are a few examples.