I think the measurements systems are so mixed up between Metric and Imperial because of the very long history of measuring things in Britain and also what kind of a 'feel' people have for things.
A stone is roughly 14 pounds and was commonly used to measure a persons weight. Unless you fought in boxing or martial arts competitions then you're measured in kilogrammes.
Lengths are especially mixed up. My Father was a farrier and blacksmith, so he used feet, inches and fractions of inches. I use mostly millimeters (actually we both use a mix depending on what you're doing). I have a good feel for an inch, 10 mm, one foot and a Metre, but I prefer yards for shooting distances etc. (archery, not allowed firearms). If I have to run a bit then I think in Metres
Temperature is an interesting example, because for warm temperatures I use Fahrenheit but in the winter I use Celsius, again I think because I have a good feel for what 75 degrees Fahrenheit is but not 32 degrees Fahrenheit, I do however know fairly accurately what 0 degrees Celsius and lower 'feels' like though (mostly feels like you want to go inside ).
Petrol (gasoline to you colonists) used to be measured in Gallons. However it was cleverly realised that by suddenly switching to litres, people would get confused and forget just how expensive it was getting. People still tend to measure fuel economy in miles per gallon however.
Measures in public houses are interesting, some spirits are measured in Gills, lost of people drink their beer in pints and often quite a lot of pints before going outside and looking for fights, which are measured in aggros and arrests.
