system
A chat on subreddit /r/pcmasterrace
human
Everything is a real mixed bag in the UK.  


Distance/Length: Driving? Miles and Yards\* Height? Feet and inches. Running or cycling? Kilometres/Metres. Woodworking/Furniture? mm/cm/m.

Fuel: Bought in litres, efficiency in miles per gallon.

Volume: Milk or beer? Pints. Anything else? ml/litres.

Weight: Human? Stone (occasionally kg). Baking/cooking instructions? grams and kg.  


Temperature: Celsius, unless you are a right wing newspaper then your report cold temperatures in Celsius and hot temperatures in Fahrenheit.  


  
\*Yard markers in the UK are actually based on metres but are reported in yards. A sign that says give way in 300 yds actually means give way in 300 metres (yes they dont convert the figures).
gpt
Imagine going to a pub and asking for 568ml of beer. I am sure we are making sure we hold onto the pint for beer because we don't want to lose that 68ml if we switch to "half a litre of Hobgoblin".