These things come in waves -- one week, everything I edit has jerky, arrhythmic dialogue, and the next week, it's all clumsy tags or draggy exposition or murky motivations. I don't know why it happens that way. It has an almost woowoo metaphysical feeling sometimes, something like when three people in a row will randomly mention their car tires to you, and then you get a flat the next day. Things just clump up like that sometimes.
So a while back, I had a run of about three weeks in a row where everything I edited led to in-depth discussions with authors about whether they were accomplishing their authorial goals. The conversations went something like this:
Me: We need to understand why the character does XYZ here.
Author: He does this because blah blah blah....
Me: But that's not on the page.
Author: Okay, but, he wants to blah blah blah....
Me: Then put it on the page.
There are two basic problems underlying conversations like this one. First, the author is sliding into defending the work instead of fixing it -- a common problem in critique relationships, but not something an editor is likely to engage in. We'll listen to a certain amount of that, sure, with the goal of helping you to fix the work. But at some point, it has to stop being about what the author hoped to write, and start being about how to write it better. In other words, it's not enough for you to tell me, "This is what I was trying to do here," unless that defense leads to a solution.
And that leads to the second problem underlying these conversations. The author had a clear idea for the scene and characters, perhaps, but it's not coming through on the page. An author can defend it up, down, and sideways in a conversation with her editor, and it's not going to put any extra information on the page.
And the author will never get to have that conversation with her readers. In the end, the only thing the reader will have is the actual text, the actual words on the page after the book is finalized and sold to her. Those words have to tell the story in a way that makes sense. Those words have to satisfy the reader's desire for interesting and coherent characters, strong and dramatic conflicts, and scenes that appeal to the mind and the heart. (And maybe other parts, too, if you write erotic romance. heh Related note -- I once had an author who forgot to write the climax to a sex scene. The scene itself was a good five or six pages long, so it was well developed and certainly entertaining. Just no, er, fireworks at the end. Luckily, that was an easy fix of the "get it on the page" variety.)
Now, we're not talking about secrets and mysteries here. We're talking about ordinary motivations and information necessary to scene and plot development. Get 'em on the page, and if someone tells you, "I don't understand this," resist the urge to defend. Channel that energy, instead, into a revision that will make everything clear to the next reader.