Anti-metrication is the process of rejecting the metric system in favor of a different system of measurement, typically the American or the different UK Imperial one.
Efforts to prevent metrication have largely failed except in the United States.
The basic philosophy of anti-metrication is that non-metric systems of measurement were developed organically from actual use (thus units which share names with physical objects, such as the foot, hand, barrel, cord) and are therefore properly suited for normal usage, whereas the metric system is based on easy decimal conversion between various units, not natural usage.
Moreover, anti-metrication is a form of traditionalism, looking to a history of usage that stretches back centuries or even millenia.
An exception to the above rules of thumb is Fahrenheit vs. Celsius, as Fahrenheit was not properly calibrated on its intended scale, and Celsius evenly divides temperature between the freezing and boiling point of water. (The scientific unit of temperature, Kelvin, is calibrated on an absolute scale.) However, Fahrenheit's higher resolution is more useful for describing air temperature.
The units that have defied metrication are temporal: the second and minute are measured in 60-unit increments, the hour in 12 or 24 unit-increments, and the day, week, month, and year maintain their historical units which are based on the Earth and Moon's rotation and orbit.
See also: metrication