Other than geography and history, pretty much 100% of our education is in metric. Honestly, every single "look, in metric this is easier because..." example that has been mentioned in this thread is explicitly demonstrated in a classroom, thoroughly explained (I want to say somewhere around 5th to 8th grade?), and then the students USE all this stuff for all their coursework for the rest of their academic life. So to everyone who thinks they're a special snowflake for realizing the conveniences of metric? I bet most of your countrymen under the age of 90 also learned these things in your schools. So you're not that special.
But after they graduate, Americans go into the real world. And our construction industry is imperial. This drives the tool market. E.g., even though our tape measures have both, TBH, inches is always marked more prominently. To this day, I have never seen metric drill bit set in a store or online, even. Other than my tiny PCB drills. The construction industry uses the tools that make their life easier, and this is what Jack and Jenny get to choose from.
So Americans adapt and are for the most part completely comfortable with either system. It's not like I feel metric "taints" imperial or vice versa. I see both as a man-made arbitrary constructs, and I use the one that works best. While driving on our roads, mph seems about right for some strange reason. Maybe some of you can explain that one.
While fabricating stuff, I use imperial cuz my tools for this are slightly better/easier in imperial, IMO. I mean, I know how to make a 1M solution of salt by using the atomic weight, Avagadro's number, and weighing out the grams into a 1L flask before filling with water to the line. But I don't actually do that very often, so I don't lose any sleep if my measuring cup is literally a cup. And I have no problem to convert that same recipe to any size in any unit. Or I could calculate "Pedro's Number," which will produce the weight of a mole in grains or ounces. Or I could calculate "JoeBob's Number," which, multiplied by the atomic weight, will give the lbs per barrel, for mixing up barrels of molar-concentrated solutions.
Internal Calibration:
I would say I primarily "capture" or estimate distance in imperial, due to my environment. You don't learn that in a classroom by reading and doing abstract problems on paper. You get become calibrated when you start to do things in the real world and actually have to measure and cut and deal with resulting accuracy.
Weight? I dunno. Pounds mostly, but for light things w/e. Grams, usually. Grains for lighter stuff (yeah, I have reloaded ammo). To me metric ton vs imperial ton? Honestly, I will look it up if/when I need to know. I'm not sure if a ton is 1000 lb or 2000lb?
Volume? Equally comfortable with gallons or liters or cups.
You metric guys listing furlongs and tower oz and whatnots, ad infinitum? You guys seem to know more antiquated and stupid imperial units than we do. We Jacks and Jennys use the basics.
If you wanted Americans to LOOK like we're metric just like Canada, then we would have to change road signs and legal stuff and to make some international announcement. Documents. Media/news. That's gigantic mess for the next 80 years.
If you wanted Americans to think in metric and are upset about tools/fasteners, then I would focus on the construction industry and media/news. That is a much more manageable problem, I think. But still expensive.