I do not wish to counter with a list of Americanisms that British people find infuriating, as life is short and we might all expire before I was done.

I will note that — unlike in Europe where metrication and SI units have been legal requirements since 1973 and are in wide use outside of the scientific community — America has no agreed upon “system of weights and measures” as you put it, instead considering the adoption of any standard “voluntary”, which makes a farce of the very idea of standardi[s|z]ation[1].

https://gizmodo.com/the-white-house-says-you-can-use-the-met...