Director - Paul Verhoeven

When antagonist Clarence Boddicker (Kurtwood Smith) is taken to the police precinct after receiving a solid whooping by RoboCop (Peter Weller), Boddicker spits a bloody glob onto the paperwork of the desk sergeant, followed by the line "Give me my f*ckin' phone call!"
Smith and Verhoeven briefly had discussed the unscripted moment before filming the scene but neglected to inform the extras - which was evident by their real and disgusted surprise as the scene unfolded.