A related gripe of mine is when precision magically appears when conversions occur. 2.2 stone is 14 Kg if you maintain the same precision.
I think in part that contributes to the metric system being perceived as complicated.
- "Keep heater 3 feet (0.91 meter) away from flammable items"
vs.
- "Keep heater 3 feet (1 meter) away from flammable items"