I feel like right-handed people would prefer anti-clockwise stairs though, because if you're carrying something heavy it's usually harder to climb up than down,

I feel like right-handed people would prefer anti-clockwise stairs though, because if you're carrying something heavy it's usually harder to climb up than down, and in my experience is more comfortable to carry a bulky object on the outside of the spiral case than on the inside. And as far as I know right-handed people have always been more common than lefties, so having more clockwise than anti-clockwise staircases is counterintuitive to me.