it's nice to know that not everything has a happy ending.
of all the times the bad guys lose and the good guys win, it's nice to know that some bad guys tried to be good and good guys are just dumb.
maybe some good guys are not necessarily all that good and bad guys may not be all that evil after all.
it's nice when you hero dies and the bad guys win. or when the hero's love interest dies leaving him lonely for the rest of his screen life.
refreshing.