Character Rebellion?

Is it possible for characters to rebel? I was thinking about this when I was writing last (which, granted, was a while ago...getting ready for the graduation party and trying to get scrapbooks done suddenly took over my life) and I'm putting my characters for "Nor the Battle to the Strong" through a whole lot of crap. And it's just going to get worse. The torment I have planned for them, particularly Liz, is kind of ridiculous--but so necessary for the story. Anyway, I got to thinking...since characters eventually take over the story, can't they rebel too? I mean I'm pretty stubborn, so I don't think my characters could win that battle, but I have gotten way past the point when my characters are acting on their own accord. They say things I never thought they'd say...argue about things I never planned them to argue about. I know other writers understand this phenomenon that I'm talking about.

It's funny writing for Liz. Because my story takes place in two different years, fifteen years apart, when Liz is normal in one section, she's angsty in another...and then it switches. She's suddenly gotten really quiet and submissive in the "past" portions of the story...and she's gotten increasingly frustrated, scared, and angry in the "present" portions. It's crazy. I can't control her anymore. I'm going to be really interested to see how she reacts when I throw the worst of the crap at her in another handful of chapters. It's still a while away, but it's building up and in some way I'm really looking forward to writing that part of the novel.