When anger is not trampling roughshod through our nervous system, it is sitting sullenly in some unspecified internal organ. "She's got a lot of anger in her," people will say (it nestles, presumably, somewhere in the gut), or, "He's a deeply angry man" (as opposed, presumably, to a superficially angry one). If anger isn't released, it "turns inward" and metamorphoses into another creature altogether.
