"I'm talkin' here!" is my favourite expression to put unruly, know-it-all characters in their place.
You know the type. They're supposed to follow the plot I have in mind and not wander off on their own, taking my story to hitherto unimagined regions that put all my pre-story-processing to waste.
It doesn't seem to matter how clever I think I am, and what foreshadowing I've engaged in, my characters tend to rule the roost. Frustrating!
At the moment I'm grappling with a scene where the lovely, but tough heroine is infiltrating a building. She's supposed to do it with stealth but on the way she gets annoyed with some drunken louts who had the cheek to whistle at her. Now, three seriously maimed guys lying in the street does not 'stealth' make. I suddenly needed to have a busy street that for some reason went quiet for a two minute time period - urghhhh!
Still, she kicked arse - so I'm not entirely unpleased with her...