I'm an American. I grew up with American standard.
Then I began taking science courses in high school and college where we used the metric system. Got several jobs in manufacturing where we also used the metric system.
After that, it began leaving a bad taste in my mouth whenever I had to use American standard... especially miles instead of km and Fahrenheit instead of Celsius.
American standard units just make no sense whatsoever. Our units don't even have their own definitions... they're pegged to metric units! The inch, for example, is pegged directly at 25.4 mm.
I simply don't understand why we keep using this ridiculous system of measurements. I know we're "technically" a metric country... but it's soft metric... they'll sell a gallon of milk and put, in parenthesis, "3.78 liters". That's not metric. That's a cop out.