The units for energy are indeed weird, even within the SI derived system we have Joule, erg, watt-hours and watt-seconds. Then marginally related to the SI syst

The units for energy are indeed weird, even within the SI derived system we have Joule, erg, watt-hours and watt-seconds. Then marginally related to the SI system we have electron-volts and the Calorie. The Calorie is also weird because most often they mean kilo-calorie when then say calorie. At least on European packaging this is truthfully abbreviated to kcal while Amarican labels just lie and say Calories. Then we have kilo-tonne, which could be a unit of weight (I wonder why mega-gram never became a thing in stead of the tonne) but is usually the explosive power of an equal amount of TNT. And none of the above had any of the American eccentrism we all love to make fun of, which have in addition to the aforementioned BTU have their own foot-pound and foot-ounce (when I pound on your door I exert a force of around 4.5 newtons on your door; and my ounce of strength is just one-sixteenth of that force).