Jokes aside, the American representation of dates mm/dd/yy has never made the slightest bit of sense to me. Logically one would either order things from least-to-most significant (dd/mm/yy) or the other way around (yyyy-mm-dd). Mixing them up just seems horribly confused and is certainly confusing (needless cognitive load) when confronted with something like 3/6/2018.
I've always lived in the United States but I've been won over to the logic of Month/Day dating format vs. our silly Day/Month format. Since I cannot go around in the States dating my checks (not cheques) 12/3 to indicate March twelfth, I use ISO 8601 date format: YYYY-MM-DD.
What I like about that format is it's unambiguous for both U.S. and foreign observers. (I work in a multi-national company.) It's month-first for U.S. readers, but it's also clear to the rest of the world that the month is in the middle.