Explanation:
A woman thinks her boyfriend is acting strangely because he's about to propose, but the audience knows that he is planning to run away with another woman, intensifying emotions.
In a scary movie, the character goes into a house they think is empty, but the audience knows the killer is in the house. This increases the suspense.
Sometimes a person is in disguise and the other character talks with him as if he is someone else. Since this is known by the audience, it adds to the humor of the dialogue.
In Shakespeare's Romeo and Juliet, the audience knows Juliet is in a drugged sleep, so when Romeo thinks she is dead and kills himself (followed by Juliet doing the same) it increases the audience's shock.
In Ibsen's A Doll's House, the audience knows Nora borrowed money forging her father's signature and her husband is unaware. We also know Nora's husband thinks of her as a doll and Nora is unaware.
In Shakespeare's Hamlet, we are aware that Hamlet knows the truth about his father's murder and that Hamlet is not mad. He is simply deceiving others so that he can plan his revenge. He does not reveal his true feelings to the other characters but the audience is fully aware of them.
In Shakespeare's King Lear, we know that Lear's most loyal daughter is Cordelia and he can't see it.
In the Star Wars movies, Luke does not know Darth Vader is his father until Episode V, but the audience knows sooner.
In Shakespeare's Macbeth, the audience knows that Macbeth acts loyal to Duncan while planning his murder.
In the TV show Smallville, Clark Kent comments that in the future he does not want to put on a suit and fly around but the audience knows he will.
In the movie There's Something About Mary, the audience knows that Ted is being interrogated about a murder but Ted thinks he is being arrested for picking up a hitchhiker. His words are funny because of his misunderstanding.
In the movie Toy Story, Buzz Lightyear thinks he is a real space ranger but the other toys and the audience knows that he is just a toy.
Hank Schrader in Breaking Bad is a DEA agent looking for crystal-meth producer "Heisenberg". We know that "Heisenberg" is Schrader's brother-in-law, Walter White, while Hank has no idea.
In Beauty and the Beast, the audience knows that the Beast is a prince living under a curse from the start but Belle is unaware of the Beast's true identity.
In Frozen, the audience is aware that Elsa has powers that are hard to control. Her sister Anna does not know about these powers and thinks of Elsa as standoffish and cold. The truth is that Elsa is being distant from Anna to protect her and is scared of hurting her. The audience feels for both girls.
