Lecture mode [on]
There's something that a lot of the how-to-write books talk about: specifically, the tension established by what the character wants vs. what the character needs, and how that ties into story resolution.
There's a bunch of different ways to handle that resolution: making the want a symbol for the need, for example. Or the want can be opposed to the need, and the character has to either reach the self-awareness necessary to get over what he wants so he can have what he needs--or fail to. As many ways to deal with it as there are stories, really.
The tension between want vs. need is what we mean when we say 'internal conflict.'
So, in Casablanca, you have Rick's want--Rick actually has layered wants, but they all come back to Ilsa--which is, of course, Ilsa.
But his need is to be the man he stopped being when Ilsa left him: the freedom fighter, in other words. The man with a purpose. When we meet him, he's broken, and over the course of the movie he finds a way to reclaim his honor and the man he should have been. Louis provides a counterpoint to that journey, as he's a man who has sold himself even more than Rick has, and has further to come back from.
At the end of the movie, Rick and Louis both discard their wants--Ilsa, and safety/wealth, respectively--and go off to fulfill their destiny--their need--in becoming the men they should have been.
Thus the heroic journey: character sacrifices want for need, and in the process, benefits everyone nominally 'good' surrounding him.
Unforgiven takes the opposite tack.
Okay, the title itself is a big-ass clue. And--side note--there's this neat mythic thing in Unforgiven where all the characters are aspects of the same character--they're all sort of funhouse reflections on the Clint Eastwood character, Bill Munny. (Gene Hackman's sadistic sheriff even has the same first name)
Hackman's character, Harris' character, Freeman's character, Jaimz Woolvett's character (whatever happened to him?), even the cowboys with the bounty on their head and the cut-up whore. They're all the people that Bill Munny *could* have been, better or worse people, shadows and reflections. The dialogue supports this reading, as Munny and others throughout the story say, over and over, variations on phrases like, "I'm not like you," "You ain't like me, you ain't ugly like me," "I want to be just like you," "We all got it coming," "I ain't like that no more."
Okay, done with the neat thing.
The conflict arises, again, over a woman who is no longer in the picture. William Munny was a bad man, one of the worst men. A shootist, a scoundrel. Whose wife, now dead, he says--cured him of all that. She's dead now, and he's raising their children alone, and the way to get money is to kill a couple of cowboys who 'got it coming.'
And in the inverse of what happens to Rick, Munny trades what he needs--the salvation and the sort of fragile peace he's attained--for what he wants, which is a more secure life for his children. And he destroys himself in the process, which is something that the end of the movie makes clear.
What's interesting--what saves the film from utter darkness--is that in process by which he dooms himself, and some of the other older, more broken versions of himself, he also saves the younger version epitomized by the Schofield Kid. "I ain't like you."
Nice to know all those critical theory classes haven't entirely worn off....