Characters on stage need motivation - as much as I hate that old 'what's my motivation' chestnut. It's more nuanced than that, and also, if you're the actor, it's literally your job to work out motivation based on the script. I'd say 'that's a rant for another time' but it isn't. It plays directly into our topic this week: Carbon Copy Characters.
How many Hamlet movies do we have? I can think of three off the top of my head. There are scads more. While the words for Hamlet never change, and the action of the story never changes, the character changes between movie versions because of the person playing the character. Each individual brings their own experience, their own emotional weight, their own interpretation to the lines that haven't changed in hundreds of years. I think my favorite illustration is the Unsolicited Advice skit. 8 actors and 1 crown prince read a single line of Hamlet's soliloquy - for comedy, of course, but you still get a sense in that bit of how different each of their Hamlets would be.
Authors working with characters need to take a cue from the great variety of Hamlets across the history of the play. Go to YouTube and search 'To Be or Not to Be'. Look at how many videos come up. What makes us willing to watch so many Hamlets?Because when we watch Hamlet, caught between life and death in one short soliloquy, we aren't watching a single character grapple with suicidal ideation and the fear of mortality. We're watching individual human beings each bringing their own fears, their own disappointments, their own unique sorrows to bear. We're watching THEM as Hamlet, not Hamlet played by them. Fine distinction, but it matters.
For authors, that translates to bringing unique wounds to each character we write. I suspect this is much easier for character driven writers than for plot driven writers. Because a character driven process begins with characters and finding character voices, it's never a conscious thought for me to make characters across books different from one another. It follows naturally from my need to understand how each character starts a story broken. It's from that place of brokenness that plot flows. Even if two characters share a basic wound - it isn't safe to trust others, for example - that wound will have come from different experiences. The responses to that common wound will be utterly different based on who these people are.
Creating unique characters isn't about what they do. Sally in this book is a hairdresser, and Sarah in that book is a truck driver. That's window dressing. What makes these characters distinct from each other is emotion. Their responses to conflict and obstacles. They likely have different goals and different tactics they use to achieve their goals. Those are the tools in the writer's toolbox that build characters that will stand apart no matter how many books - or Hamlets - you subject yourself to.