
If I had a nickel for every time Derek told me I loaded the toilet paper the wrong way, I could buy a ton of... toilet paper. In order to send a clear message, by beloved sent me these diagrams.

Line of sight is an important aspect of toilet paper grasping. As you can see here, the over-hung method is far more conducive to proper grasping; this leads to tearing, which will be explored in the next image.

In order to avoid detrimental momentum created by the one hand tear, "over" and opposed to "under" is essential if you don't want to waste precious TP.
For a full explanation, and the site of the original genius, go here.