The unlikable narrator is surprisingly likable. Quinn is a violent junkie raised by a violent dad and an alcoholic mom (if I remember which is which correctly, or if I'm not blending the details with those of some other book I read recently), but for a middle-school dropout, she has an impressive vocabulary. "...fear of losing such a sacchariferous deal."
In the tradition of the smart and smart-ass addict, her voice brings Jim Carroll to mind. "Once I was pronounced clean, I was led through three parlors, their walls plastered with velvet wallpaper, each room a different garish color, and each decorated with a confusion of threadbare antique furniture." (nb I haven't read Carroll in probably twenty years, so I may be wrong about the similarity.)
Maybe I just like Quinn because like me she says "thank dog" for "thank god." And I like that she happens to be gay.