I dont even wanna know how they started with mm-dd-yyyy. Just as illogical as a gallon or mile
I know I had this discussion with @Machina awhile back, but even "speaking" a date in the US is apparently different than the way you Europeans would say it (which is obviously what leads to the different formats). Whereas I would say, "Today is May tenth, two-thousand nineteen" - you all would say, "Today is the tenth of May, two thousand nineteen".
...what's interesting is that no matter where you are from, just the other method of speaking a date feels completely foreign.