As you know, Bob… there’s a right way and a wrong way.
Exposition in a screenplay is how the writer informs the audience about information they need to fully understand the story. It’s a skill worth mastering.
There are both “good” (i.e. skilful) and “bad” (i.e. sloppy) exposition techniques. Make sure you emulate the good ones. When presented correctly, the audience won’t even know it’s happening. When presented incorrectly, “on the nose,” it’s annoying and draws the audience out of the story.
Ever notice how sometimes in a movie, a couple sits in a restaurant booth and their conversation goes something like:
Rita, my dear second wife. We’ve been together for ten years now. Ever since I divorced your sister. And now our only daughter Clarissa needs braces. But since you lost your job, we can’t afford them.
Bob, you know I can’t get a job since the car accident last month. I’m paralyzed from the neck down. And I won’t be getting a fat settlement since I was over the limit. Good thing the only other thing I damaged was a telephone pole.
Yes, that’s a bit exaggerated. But it shows why bad (lazy or sloppy) exposition doesn’t work. This is a blatant example of what’s referred to as “on the nose” exposition. In dialogue, it’s a conversation that exists for the sheer purpose of filling in some info gaps.
These poor examples of exposition have other names too. Like “information dump” or, more colorfully, “Maid and Butler” or “Tell me, professor…” dialogue. Some even reduce this trope to the acronym AYKB, meaning: “As You Know, Bob…”
Find a better way to inform
There are many far more effective ways to include exposition in your screenplay.
For example, instead of Bob reciting a laundry list of exposition to Rita, and Rita doing the same, you could set your scene in her hospital room so the audience sees her injuries rather than hearing about them. A 10th Anniversary picture frame with a picture of Bob and Rita would do the job of informing the audience of that tidbit. Maybe the sister could appear in an awkward visit.
A scene showing Clarissa’s classmates teasing her about her teeth would accomplish two things: telling the story, and engaging the audience emotionally. Maybe they’ll feel sympathy and sadness, or if your story requires it, you might show her clobbering one of them. It’s all up to you. You’re the one who will write it and you’re the one who will suffer or benefit from the audience’s reaction.
In the end, it simply comes down to spending a little more time on the planning and outlining so you can insert your exposition naturally, in many places over the course of the story, rather than just blurting it all out at once in a single conversation. Be it with Bob, the butler, or the professor.