Sometimes I still convert from metric to imp simply to assess temps. 30dC = 88dF - that's warm.
Being a metric converted country, in aviation we still measure speed in knots, distance in nautical miles and altitude in feet. BUT, when assessing VMC (flying conditions), visibility must at least 5000 metres, not 3 nautical miles, clearance from cloud - 1000ft above 500ft below and 1500 metres horizontal separation.
All mixed up. As far as I'm aware, knots etc are still the International standard. Oh, and fuel calcs for some aircraft have to be converted from US gallons, as opposed to imperial gallons, to litres, different again
Cooking measures can be confusing, because an imp cup holds 230mls & a metric cup holds 250mls, a cup of flour weighs 130gms or imp 120gms. I have to be careful which measures I use because the mistakes are almost outnumbering the successful conversions.
The US is halfway to "metrification". Dollars & Cents have virtually trained you guys. On Feb 14, 1966 we changed from L.S.D. or pounds shillings & pence to decimal currency. That was a rort - if all your money was assessed in Pounds, after that date you automatically lost 20% of your worth off the top. 24 shillings = 1 pound = $2, 20 shillings also = $2.00. I was poor and young so it didn't matter. The math was crazy, but fun to learn. Our British brothers & sisters have also done the same exercise - changing from LSD to New Pence and they are still with us.