Why does rubbing salt in a wound hurt so much?As a metaphor, “rubbing salt in a wound” means to make an already-bad situation worse for someone, especially in an unnecessary or gratuitous way. One hears the phrase constantly, about everything from taxes to sports. Perhaps one reason it’s so common is that, even if most of us have never literally had a handful of Diamond Crystal rubbed into an open blister, we intuitively understand it to be painful, even unusually painful (after all, th...