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If Americans use the metric system in America, is it considered misappropration of culture?

We use it, I think, mostly because of how expensive it would be to change all the signs and whatnot.

For MPH and stuff, yeah, it's the expense of changing all the signs. It's not even just speed limit signs, there's also all the mile markers and then the signs that tell you how far away towns/cities are and stuff. For Celsius vs Fahrenheit, it's mainly because most of this country wouldn't be able to handle it because either they forgot it or they were too stupid to learn it in the first place. Anything in STEM in college, except maybe a reminder your freshman year, will be done with the metric system... and any of those jobs in a STEM field will use metric.

Australia converted usa could too.

I'm pretty sure the average Australian is much smarter than the averaged American.

We will never know, because even if it's true the Aussies obviously cheated and the whole system is rigged. Plus guns, oil and freedom (bald eagle skreetches)

Skreeeee... speaking upon eagles, I had a brown eagle swoop down next to me on the patio the other day; so close if I had known it was coming I could have reached out and flicked it's wing. That thing was BIG. Even the ravens that'll harass hawks away were all like yeah, fuck that...