Even at my advanced age (50+ forum member) that's lived in the States for all but 3 years of my life I'm ambimeasurable and it depends on the setting.

If I'm working on an automotive motor at a machine shop I can say - "grind the crank 10 under" and it's known what that means. I wouldn't say - grind the crank .254 under or even better... grind the rod journals to have .0127 and the mains to have .02032 clearance. I'd say 'grind the rod journals to have five-tenths and the mains to have eight-tenths' because it's known that five-tenths is = .0005 inches and eight-tenths is .0008 inches.

Do I still grab a 3/16 when the 5 is supposed to be used? Yeah, sometimes.
Do I put a "u" in color? Yeah, sometimes when I'm typing an email to a co-worker.
I'm just as comfortable saying I've lost 5st 5 in the past 15 months as saying I've lost 78 pounds

Do I feel 'forced' into using the metric system? Not a chance on forcing me to do much of anything.