Toilet paper should always be hung so the paper comes out from the top. People who have it come from the bottom are misguided and need to see the light. Over the top is easier to control the amount of paper and the speed at which you want it. There is also less chance of the paper unrolling all the way to the floor and becoming unsanitary. Lastly, when in the over the top method, you will always know where the paper begins, but with the under method it can be difficult to locate that beginning paper.