Writing pet peeve
There are two lines of dialogue that I absolutely cannot stand. They are (drumroll): "I have something to tell you" and "We need to talk." No good comes after those lines of dialogue are uttered, and more likely than not, it's something majorly dramatic, and usually concerning a surprise bundle of joy.
There's nothing inherently wrong with the dialogue itself, but rather that it makes for a clunky set-up. It removes the subtlety from the situation and puts the anvil in motion, broadcasting, "Reader! Pay attention! Something important is about to happen! The plot is going to move forward!" It's moving plot forward through dialogue, rather than the actions and feelings that result from said dialogue.
I'm a big fan of characters talking and discussing their issues, but do they really need to announce that this is what they're going to do? Can't they just sit down and do it? There are ways of accomplishing the same thing without being as awkward and anvil-like. Conversations, in the real world, just happen. They are spontaneous, and nine times out of ten, we're not thinking about the words that come out of our mouths before they're out there. And we don't always give speeches about Issues (tm), and more times than not, we tip-toe around the thing that's going to cause us pain.
Written dialogue should reflect that same reality. I like Hemingway's sparse style of dialogue, where more is said between the lines than what the characters say, but that's Hemingway. The trick is to find the balance between broadcasting the plot intention through dialogue and coming up with realistic and intelligent dialogue that keeps the reader guessing.
When I figure out how to do it, I'll let you know.