Dave doesn't like Amy because he despises her lifestyle. But is she ugly? More of a strange bird (though not my type at all) in the Patti Smith (I thought Patti pretty) vein of things. I once spoke to my teenage daughter about Amy vs. Duffy ("Mercy") and she said: "Duffy is just hopping on some train, but Amy, the way she sings and looks, her style, that is totally original and cool". She did not deem the alcoholic, anorexia and other drug excesses "cool" though.
