I have thought about this many times my self.
it can be done though. Look at the godfather for example. micheale starts out hating his fathers ways and claims he would never become a man like his father. he starts out innocent and a war hero and eventully through circumstances..(the killing of his brother and fredo being inept) he sinks into the abyss of his fathers ways and by the end of the movie he is even worse than his farther.