Technically all arbitrary, but Fahrenheit is definitely on a whole different level of arbitrary.
Celsius - 0 = precise freezing point of water and 100 = precise boiling point
Kelvin - same as C, but shifted so 0 is the precise lowest possible temperature
Fahrenheit - 0 is the imprecise freezing point of some random brine mixture, 100 is the imprecise average body temperature of the developer
That was a long way of saying what I said, you just don’t see faranheit as ludicrously out of date, while I (and most of the world) do. Live your life as you wish friend. It’s a random brine mixture. Maybe it was less random back then, but now it’s an arbitrary mixture of water and salts in arbitrary ratios. Deal with it. Fahrenheit sucks.