When I was growing up, anytime I encountered anything chocolate, it was usually milk chocolate. And while I would eat milk chocolate, it was sweeter than I preferred. What I really liked was dark chocolate, with its bitter edge.
Not everyone likes a bitter edge. In fact, one of the surprises of my adult life has been the new popularity of dark chocolate. I'm enjoying that, because it means more dark chocolate is now available more places than ever before. Maybe it will be a fad, and in a couple of years everyone will go back to milk chocolate. Well--almost everyone, because I'll stick with the dark.
When I mention that "bitter edge," it makes me think of my taste in fiction, also. Contemporary realism is like dark chocolate in that way. Often, these are the books that cover darker topics. Some people find them too bitter, but many people find just what they need: a depth and richness that is satisfying in its bittersweetness.