I'm not sure what the situation is in other European countries, but in the UK we use different units depending on the use so most people are use to working with both imperial and metric.
Perhaps with the exception of fahrenheit most people here will know what you mean if you use units like feet and will often even prefer thinking in feet over metres for certain things. Personally I default to feet for something like height or a floorplan, although I can think in metres quite easily too.
