When you really break it down, wrapping paper represents a kind of psychological torture.
It's a perfect tease: allure and obstruction in a single device. At once, it indicates that this is a gift, something good that was bought with the intent of pleasing, while simultaneously acting as a barrier to that very thing. It inspires intrigue about what the contents could be,and holds the promise of something that will be yours-that is yours actually. By all rights, the tag on the outside secures this object of mystery as your property. You can take it, even carry it with you if you like.
But you can't open it.
If you open it, you're a bad person. To have that thing that's yours before an communally agreed upon time would make someone sad, the same person that chose to do this nice thing for you/force you into this trial of human will. And the icing on this cake, what we can now recognize as some sort of devilish butter cream, is the knowledge that wrapping paper is so easy, and so fun, to remove.*
*And sometimes then there are Legos.