Honestly, it’s the constant imperial / measurement changes that piss me off as a Brit.
Liquids are Metric unless it’s Milk or Beer (Which can and often are sold as both… in the same shop, you will find 1pt, 2pt, 4pt and 6pt milk right next to 0.5L, 1L and 2L bottles of pop. And you’ll see in some places 660ml beers being sold alongside 2 litre ciders)
Distances in Metres when it’s swimming pool length, running tracks & fields. Yard, Foot and Inches when it’s Height, Football, Snooker Cues, Carpets and pretty much anything else you can think of
Weight is Metric when it’s food, unless it’s a steak or a burger. Imperial when it’s a persons weight.
Car efficiency is measured in Miles Per Gallon, but the Fuel is sold in Litres.
Recipes for cooking food can and will contain both measurements as well as cups, which is even more confusing.
Trying aviation is just crazy (I used to fly occasionally from Cambridge to various places around the UK). Fuel uplift is in litres. Fuel gauges in kgs. Runway length in meters. Altitude in feet. Pressure in hectopascals. Wind & speed in knots …
I was trying to help my brother with some maths homework where they wanted him to poor different liquids into different container to see what was larger 1/2 pint or 330ml.
I had to explain to him why we used different measurement for liquids, it was impossible to explain besides its just how it is as we’ve never moved on.
The worksheet needed a measuring jug in both pints and mils and cups. I had to convert fluid ounces into pints so I could do that homework it’s stupid, as he’s six!
Honestly, I was nearly wanting to go metric!