I was taught all metric in school and university. I understand it very well.
Growing up distance was in Miles, then Km. Now they Switched speed to Km as well. but everyone still uses miles/hour and miles as far as i can see.
And when i enter the 50km zones, i keep the needle on the 30. (as focusing on the tiny 50km/hour gauge is impossible)
So i use MPH in lfs, it just seems natural, in the same way that mass is kilos, volume litres (except for petrol use which is miles/gallon) and beer comes in pints. Engines have CC capacity, but BHP power.
In short i think we need to go cold turkey, and abandon old imperial units, but its hard, as you can see from the experiences above.