I hear that a lot, but I don't understand it. You're the person in charge... if your characters won't behave, fire them and bring in a new batch!
As for me, it's my mind that seems to have a mind of its own. It doesn't want to write the story that I have meticulously plotted and outlined... it wants to write the story that I haven't plotted, outlined, or developed characters for. I have no idea where this story is going, but it's really easy to write at the moment...
Mine behave. It's just that currently they're not talking to each other...because they apparently aren't in the same story...