The Bad Seed was pretty good. It was based on a play and was a bit stagy. The dialog wasn't entirely naturalistic. But the situation was stronger than the weaknesses. A mother comes to realize that her seemingly perfect daughter might be terribly bad. With Patty McCormack in the title role. She got an Oscar nomination for it. Also got spanked in the end even though this was after the curtain call---she was in costume but not in character. They were spanking the actress for playing a psychopath.
The movie had a couple of scenes of Leroy the handyman talking loudly to himself and to the audience. I'm sure this was fine in the play, but it didn't quite work in the movie.
Somewhat like this other movie, Richard III, starring Lawrence Olivier. The movie was in technicolor, brightly lit. A bit cartoonish, not like Polanski's Macbeth or Welles' Othello. So the scenes of Olivier walking around reciting soliloquies weren't terribly realistic but there was no illusion of reality to begin with. If the guy was just walking around muttering to himself, they might have pulled it off.