Why are there two types of faucets: right-hand and left-hand (clockwise or counterclockwise)?

I don’t know what kind of faucet you are referring to.

Both stop valves and gate valves adopt the design principle of opening counterclockwise and closing clockwise. Old-fashioned faucets are stop valves.

Water valves commonly used in home decoration, such as hot and cold water mixing valves, angle valves, and quick-open faucets, are all ball valves. The opening and closing of the ball valve are related to the rotation angle.

Ceramic valve core ball valve