Whoever said Wikipedia, or Sciencebase come to that, was trivial? This is meaning-of-life stuff: Toilet paper when used with a toilet roll holder with a horizontal axle parallel to the wall has two possible orientations: the toilet paper may hang over (in front of) or under (behind) the roll. The choice is largely a matter of personal preference, dictated by habit.
via Toilet paper orientation – Wikipedia, the free encyclopedia.
By the way, this is an example of conversational entropy…if you talk to people long enough the subject matter will inevitably fall to the lowest common denominator, which is usually bodily functions of one sort or another…seeing as well we all have bodies…and functions…