Deana frowned. “Why don’t we just turn him over to the police?”
“Well,” Artiom replied, “as you know, I’m involved in a few . . . less-than-legal activities. If I turned him over to the police, he could rat me out.”
This is a small example of what is often called “maid and butler” dialog—dialog wherein character one explains something to character two which character two should logically already know. The worst examples of this are scenes in which two supporting characters (a maid and a butler, for instance) have a conversation about plot-important information that they both already knew.
The problem with this sort of dialog is that it breaks the fourth wall (and not in a good way). Since both characters already know the information, the only reason for them to explain it to one another is for the benefit of the readers. And if the only reason your characters are doing something is “because the plot demands it” or “so that the readers will understand,” then you haven’t written the scene well.
The phrase “as you know” almost inevitably introduces maid-and-butler-esque information. After all—if someone already knows something, then they don’t need it explained again. This phrase highlights awkward or stilted dialog, ensuring that no one will miss the fact that this dialog is awkward and unrealistic. Avoid “as you know” whenever possible (which should be practically always).
One of the most common ways to avoid maid-and-butler dialog is to insert a character into the story who is not familiar with what is going on or with the most basic information about the world. This character can be a sidekick to the protagonist or even the protagonists themselves. Harry Potter, for instance, was raised without any knowledge of magic and the wizarding world, so it wasn’t awkward for him to need constant explanations about things that everyone else knew. These explanations were simultaneously helpful to the audience without feeling forced.
Another common method for avoiding the “as you know” problem is to have character one explain something that character two knows (but the audience didn’t), and then have character two get irritated over it. Just make sure that character one has a plausible reason for thinking that character two wouldn’t know the information. But be careful about using this method too often—it can grow very tiresome very quickly.
Other phrases that often lead to this sort of awkward, in-dialog expository infodump are “let me get this straight” and “tell me again.”
Maid-and-butler dialog is a cliché that most writers encounter over and over again—it can just be so difficult to get exposition through in a smooth, natural-feeling way. But don’t give up. Keep trying, keep looking for new ways to share exposition, and you’ll almost always find something better than “as you know.”