
"I'm going to the store," he said.
"Okay," she answered.
"I'll be right back."
"Okay."
"See you soon."
"Right."
2. "The generator for the EV-365 is a double charged lithium hydrogexenator, that has duel

"So you're saying that it's the lithium hydrogexenator and the charmeuse lasers that are the key to success? What about his later models that worked without these things? The AWBB-48-00? Or the TRP-45-68759?"
We call the first treading water. That is, small exchanges where information that doesn't move the story forward but just fills space. The second is using dialogue as an SUV for information.
In both instances, the information may be imparted in a different way --compacted, parsed and exchanged for a stronger scene. Dialogue is difficult. First attempts will almost always be redundant. Often they will impart far more information than needed. And sometimes the reader is being told what he or she can already infer.
Dialogue in writing is much different that dialogue used in scripts. In movies, you can have exchanges like the one above because you have a supporting cast of environment, action, light, facial or body expression and even music. But in books, too many exchanges like this become nothing more than treading water or as in the latter, drowning the reader in too much information.
Dialogue must reveal character, use only the most essential words, convey emotion, provide information and move the story forward. It is the artful combination of the right words and phrases to create the illusion of talking.

"I always try over the phrases, fooling the reader into believing that this is how people actually talk. In fact, inevitably it's far more coherent than any actual talk ...but when in doubt I will repeat a phrase to myself seven or eight times, trying to put myself in the place of an actor speaking the part."