It's funny how in Canada we have some specific remnants of the imperial system. Most people under 50 have no idea what a Fahrenheit is (myself included), except for pool water and oven temperature. Go figure.
People complain about inconsistency and lack of standards in the use of measurements in the U.S, but it is actually much more consistent there. It turns out that decimal units aren't really better for any practical purpose in a typical person's life, and it's certainly worse if you need to know both!
Even in the U.S. of course, engineers, mechanics, plumbers and others still have to deal with a mix. Think metric-based and imperial-based bolts, metric v. imperial lumber sizing.
s/U.S./the entire world/
It's very common to have international U.S. based companies offer N types of fasteners/whatever in imperial sizes, but only N/2 in metric. So we frequently build stuff in imperial sizes because of greater flexibility.
And don't get me started on (non)tapered pipe threads... I've heard some horror stories of huge subassemblies built in Europe using BSPT and shipped to the U.S. for final assembly, where of course everything else is NPT, so some poor sod has to spend a month replacing all subassembly fittings.