I've been thinking largely in metrics since high school, but there are certain cases where metric representation is just dumb. If you give body temperatures in degrees Celsius rather than Fahrenheit, your precision goes down by a factor of almost 2 (9/5, to be exact). And expressing nautical distances in kilometers is a horror: a nautical mile is one minute of arc (at the equator), which makes chart reading very easy; a knot is one nautical mile per hour.