Sarcastic dialogue uses intentionally disingenuous phrasing to highlight the hypocrisy of a situation. We’ve all known lots of sarcastic people, so this type of dialogue is certainly true-to-life and it can therefore be a strong element of a character’s voice, but it’s important to remember that this sort of intentional irony is not going to create the same amount of meaning as unintentional irony.
The audience prefers to see what the characters can’t see: We want to be one small step removed from the story, seeing some things they miss. By contrast, we want the characters themselves to be in it, not outside of it. Well-written sarcastic characters think they can see the irony of their situation, but we see that they don’t really get it. George Bailey in It’s a Wonderful Life is a wonderfully sarcastic character, but he is unaware of the larger ironies of his life until Clarence the angel points them out.
Then there are times when characters engage in Blatant Talk About Irony. This should almost always be avoided. Irony should be the air your characters breathe, but they should not be aware of it, just as we are not conscious of each breath. Whenever characters talk about how ironic something is, the audience groans.
Here’s a particularly atrocious example of the above: Bette Davis followed up her big comeback, All About Eve, with a very similar role, but this time the results were disastrous: In The Star, she played a washed-up ex-starlet who tried to settle for a down-to-earth longshoreman played by Sterling Hayden. Eventually, the grubbiness of her new life causes her to snap, and she smashes a store display to steal of a bottle of super-expensive perfume on display. This results in one of the worst scenes ever written…
- The Scene: When Hayden comes home, Davis confesses her impetuous crime and hands the unused perfume bottle over to him. He sternly lectures her, but when she breaks down crying he has no choice but to comfort her. He finally opens the bottle himself and says that she might as well try some on, but they’re surprised to discover that they can’t smell anything: the display bottle was just a prop. This causes Hayden to wisely opine: “You thought it was the world’s most expensive perfume, but it was just colored water. [Dramatic Pause…] That’s just like your life.”