One thing that non-authors simply don't believe is that characters, when they work, simply don't do what you tell them. They go off and do their own thing, they

One thing that non-authors simply don't believe is that characters, when they work, simply don't do what you tell them. They go off and do their own thing, they talk to the wrong people, they ignore your carefully designed plot entirely and get distracted by shiny objects... occasionally they'll just walk onto stage and demand a speaking role... I once discovered that one of my lead characters had an estranged daughter by reading what she'd said off the screen after I'd typed it.