I struggled with fully fleshing out some characters, particularly those who are quieter, more cautious or not in a good position to just be themselves. It occurred to me recently that perhaps character is less "who they are" and more "what has shaped them" - the things they did that they are ashamed of, the people they've encountered who helped or hurt them, the lessons they learned formally or informally.
I recall a David Mamet quote about there being no such thing as character - only what people do. In an earlier novel, I followed this and got crushed by readers for a "lack of interiority." Now I wonder if perhaps the concept is correct and I just enacted it poorly.
I'd love to hear thoughts on whether in modern lit, character is more personality or more experience, and how you bring character to life who aren't outgoing or free to express themselves.