So what your characters care about the most should shape them. I was also watching earlier this evening some of Patrick Stewart's version of Dickens's marvellous A Christmas Carol. And prior to Scrooge's encounter with the ghosts (I refuse to believe that could possibly be a plot spoiler - not now surely?!), it is very clear Ebenezer's love of money has made him the grasping, horrible character he was.
So what do your characters care about the most and why? Do they need to change their priorities? How does what they care about make them act (or in some cases refuse to act when others would)? How do they react to those characters who don't care about the same things (not well would be my initial guess (!) but how does that play out?)?
What really drives your characters is what makes them after all.