Don’t spill the salt.
Balanced seasonings tempts fate and provokes the superstitious in many ways. The bottoms of the salt and pepper vessels have no flat portion, so they cannot be placed down, lest one wants to call bad luck upon them. The stand itself is precariously stable when both vessels are attached; when one is removed the stand shifts off balance, and topples to one side. Droplets that are about to break and fall inspired the vessel form, further promoting the tenuous situation.