Star Trek II: The Wrath of Khan - Don't Do That Again!
There is a scene where the actor portraying Khan's son's hand slips of the back of the captain's chair and hits Khan in the shoulder. Kahn turns his head and gives his son a dirty look. It is towards the end of the movie, around the scenes in the nebula.
First of all, it wasn't Joachim that slipped and bumped into him, he was the guy that sat at the helm and whine about not being able to get the shields back up after Kirk used Enterprise's computer to lower them in their first battle. Second of all, how is all this a slip-up anyway? If it was unintentional wouldn't the director have edited it out? It was part of the movie!