It tickles me to bits, really. I suppose because it's one aspect (or one of several aspects...) of a book we can't control, so I can be objective and enjoy, and because it's so interesting to learn what readers think about these things. KINK has come off as the best of the worst, ie the least people voted for it to win the wost cover of 2007 award.
See all the covers and read the hilarious comments here.