When living in a foreign country you get accustomed to its idiosyncrasies and adapt, but it's still funny as hell to see other people struggle with the weirdness of a new place.
The UK is no exception to this, and despite officially using the metric system there are still a lot of things that leave you scratching your head.
So let's do a small rundown of the current SNAFU:
Distance on the scale of roads
We all know road signs, right? The plates which tell us where a certain road leads to, or after what distance a certain exit will suddenly appear. Well, in the UK they use miles for distance for distances over 0.5 miles and meters under that; so one sign says junction in 1/2 miles; then were is a 300, 200 100, meter count down to the slip road.
Distance on the scale of houses and building materials
Remember the totally typical American 2x4 (2 by 4)? Well, dimensions here are officially metric, but are conveniently foot sized. E.g. sheet plaster board is "nominally 8x4", but officially 1220mmx2440mm.
Small scale - multiples of 1/2 pints no exceptions that I'm aware of, the kegs are metric now. 50l I think.
Mostly 330 or 500ml.
Fuel petrol, diesel, heating oil, propane/butane(LPG) for use in cars
Sold as "litres" but it's really a density corrected volume that takes into account temperature and additive mixture so isn't really litres that comes out the nozzle, but there is approximately zero general understanding of l/100km as a unit of fuel consumption miles per gallon is used officially.
Fuel propane/butane(LPG) not for use in cars
Kg, unless it's tanker delivered when it's usually litres.
Fuel Natural Gas
Therms (density corrected metric-ised cubic feet).
mm and inches, there are too many old vehicles for genuine inches to have disappeared.
Weight (everything except people)
Pretty much Kg and Tonnes now.
Except amusingly, lots of things are sold in metric amounts corresponding to their imperial equivalents eg 454g = 1 pound. They do the same thing with some (but not all) liquids sold in bottles. For instance, I get my milk delivered in glass bottles of about one pint, but I suspect that officially they are actually 574ml. If I buy milk in a supermarket in a plastic bottle it will be marked in fractional litres, corresponding to 0.5, 1, 2, 4 pints. BUT if I buy say, lemonade or other sugary carbonated type drinks, it will be in a 1.5 or 2 litre bottle.
Stones and pounds.
Temperature (not the weather)
Celsius (but a significant proportion call it centigrade) and "Gas Mark" a weird unit that will not die still marked on some ovens.
Celsius, but usually with Fahrenheit available.
All clear? But hey, the British always have high standards :D