Luckily this one will die out naturally as we (the general public at least) stop using fuel and switch to buying kWh of electricity, though don't get me started on car reviews using horsepower/PS equivalents for electric cars instead of using the rightful kW measurement.Utter stupidity is pricing petrol in litres, when everyone judges fuel consumption in MPG. Petrol should obviously be sold in gallons. The reasons it's sold in litres is that the government of the time thought the price in gallons was frightening the public and they would be less concerned if it was in litres as the price would not appear to be as bad (it was just perception).
Just to keep things on topic with the OP, I think this thread demonstrates precisely why we're still using a mix of units - a combination of apathy towards finishing the change, and people on either end of the spectrum of wanting to forcefully change to metric, or forcefully move back to imperial fully