Which way should the toilet paper roll hang? Should the “on deck” square be hanging over the roll and closer to the hand that will next grab it, or is the correct way to hang the free end under (behind the roll) to seem more tidy? I can’t tell you the answer, but the folks down at engineeringdegree.net  have put together some stats and equations that may persuade you one way or the other.
This discussion came up the other day while suspended in a metal box and agreement could not be reached. We didn’t get much input from the others in the gondola that day, but according to those who do real science, some of them likely had an opinion on the matter.