I always think I have a good idea of who my characters are when I start writing a book. However, invariably the characters start to assert themselves as the writing progresses. Often, they change the entire plot with their shenanigans. Right now, I think I have a handle on my latest hero and heroine--Tadeusz and Victoria, but one never knows.
I was reminded of this when hubby and I went to eat at Charlie Brown's tonight. We were seated in a booth surrounded by books--lots of books. The temptation to pull one off the shelf was irresistible--and then I saw Andrew M. Greeley's Ascent Into Hell right within easy reach. Of course, the book was red, so it was hard to miss. Even hubby--who never reads fiction--was interested because Greeley is a priest. I read The Cardinal Sins years ago, but I haven't read any of Greeley's books since then.
I opened up the cover and found Greeley's disclaimer in the "Note." In it he said, "...like God, I refuse to assume responsibility for the moral behavior of my creatures."
Yes. Sometimes those characters misbehave--and there really isn't much an author can do about it. But that's part of the fun of being a writer--breathing life into creatures made of words.