Depends: the sheets (whether fitted and flat, or two flat with one tucked under all four corners and one lying above) are there to provide an easily-washable en

Depends: the sheets (whether fitted and flat, or two flat with one tucked under all four corners and one lying above) are there to provide an easily-washable envelope within which to couch your body while sleeping. While we sleep--and occasionally, when we use the bed for something other than sleep--we produce a certain amount of refuse: sweat, sloughed-off skin, hair, drool, etc. The sheet envelope can be pulled off and tossed into the laundry to remove that stuff--and its associated visual and olfactory attributes--from the sleeping environment. It's troublesome to haul the mattress out in the yard and hose it down, and even harder to stuff it into the dryer afterward; and some bed coverings (heirloom quilts, down comforters, etc.) cannot be readily laundered. As long as you have something washable between yourself and those elements of the bedstack, you're probably fine. On the other hand, if you're romantically inclined, and the person with whom you would like to recline romantically is turned off by how your bed is stacked, well then, yes, you're doing it wrong.