The world has a lot of different standards for a lot of things, but I have never heard of a place with the default screw thread direction being opposite.
So does each language have a fun mnemonic?
Photo credit: https://3.bp.blogspot.com/-Giy8OrYJTjw/Tfm9Ne5o5hI/AAAAAAAAAB4/c7uBLwjkl9c/s1600/scan0002.jpg
Acetylene does, gas lines are standard pipe.
Suppose it’s cause natural gas runs at like, 1-3 psi, while a fresh tank of acetylene is 5,000?
Least in the US