If you have a house that was built over 20 years ago, chances are it has an orange peel texture on the walls in at least one room. If you can't picture it in your mind, think of (surprise!) the peel of an orange. It's smooth to the touch, but still has a somewhat dimpled surface. While this may seem like a strictly aesthetic choice in home design, it does actually provide a level of durability. The extra layer of plaster protects against dings and scratches in the wall that would otherwise be noticeable and more detrimental on a smooth surface.