The characters in my plays and stories sometimes say things I would only think of! It often surprises me. At times I try to silence their voices, thinking someone will object. But they only get louder, almost shouting their release. Funny how writing does that, produces unique voices that belong to unique characters. We almost never know from where they hail.
Creative writing can be a healing activity. It reaches down deep into the soul and pulls up feelings that we give voice to. These manifest in our characters, sometimes unsavory, darkly demonic or just plain rude and crass. I love that my characters can simply flow without my censorship. When the mother or superego in me presides and prevails, my characters are mere shadows of themselves. They aren't genuine. They don't come from a place of true struggle which I think is every writer's conundrum. It's that line between writing from the heart to release one's soul and writing without a soul.
Let your characters lead and you may find they'll lead you into unchartered territory. It may be full of learning. It may enlighten and inform. But above all, it may be the greatest truth you've ever uncovered.
Do you censor your characters? Do you feel compelled to write nice or do you write from a place of truth?