I often feel a twinge of jealousy toward songwriters and poets. They get to churn out as much exposition and naked thematics and context-less emotion as they want. Add a few guitars and a talented voice, and you've got yourself a hit. No worrying about plot structure and set ups and actions, and character misbehavior, and..and.. They have no idea how easy their job is!
Of course poetry and songwriting are not easy. They're just a very different kind of writing. Drama evokes meaning not through statement, but by conflict and its resolution. To generalize broadly, songwriting and non-dramatic poetry are largely about finding the perfect statement of the subject. This is about as far as you can get from screenwriting. Apples and oranges. Separate animals. The Greeks in their wisdom gave each its own muse.
So a Leonard Cohen can find depth and meaning in his songs by drawing a particular vision in his head, or rolling a metaphor through a series of frames. kd lang can talk about love, and know that it's her voice that makes some pretty quotidian stuff suddenly strike deep in your soul.
Many new and not so new writers get caught up on this. Most writers have had a class or two in English composition. You know how to write an essay. You write a short story or two. Maybe you stick with it and learn a lot. Then you turn to screenplays with no idea how little you know.
Often writers like this have a tendency to indicate emotion, rather than showing it. A character scowls. Or a character stares at the sea. Or she crosses her arms and harumphs. And, while the situation is harumphable, something just doesn't ring true about it. It falls flat.
Let's examine where this comes from. If you write prose, then you probably had your character harumph, cross her arms, and then you stepped in with a long internal monologue or similar. If you write poetry, this is maybe an act that describes a situation very precisely -- a miracle of language.
But it doesn't work in a screenplay. Why? Because we watch a visual differently from how we read a book. Scene to scene, we expect to be inside a character's head. We're making unconscious bets about what they'll do and how they'll react, and oh no, what will happen then! While this does function in some prose, it's not as central as it is in dramatic writing.
If you drop that ball -- if you lose where the character is IN THE MOMENT -- you lose your audience as well.
Relatively new writers have a tendency to write with their own goal in mind rather than character intention. The character feels the way they do because that's (consciously or not) where the writer needs them to be.
Screenwriting is just the first step, and if, god forbid, your script full of indicated conflicts and emotions makes it through the production process, it will stand out like a sore thumb. It won't be believable, because it doesn't correspond to the audience's understanding of the character and his plight. It will look like the writer needed the character to stop breathing long enough to harumph.
Let's look at it from another perspective. Why do some writers rely so heavily on indicating? Usually it's a lack of conflict. The details of the plot aren't worked out. And the writer is terrified to let his character wander away from his plot line.
In other words, character intention has nothing to do with the writer's goal. They usually are in conflict. The new writer thinks: let's just sweep that character intention under the rug. I don't care if he's hungry and needs a bath, he's going to ask his teacher on a date.
The more experienced writer sees a huge opportunity. This pesky problem with the character is exactly what a scene needs to bring conflict. The character needs a bath -- great! He's doing everything he can to shy away from his teacher. She's getting angry that he's giving her the cold shoulder. Maybe she's eating a hero sandwich, and he can barely think he's so hungry. You've just made it next to impossible to ask this woman out. And you've done yourself a huge favor. You've grown the dramatic distance he covers. You've given yourself numerous chances for him to act and express what's going on, rather than simply indicating them. When somebody harumphs, we believe it.
If you feel your scenes falling flat, look at the scenes before them, and ask yourself what you're sweeping under the rug. It's usually exactly what you need.