Talking heads instead of narration
According to Jack Bickham, author of Scene and Structure, there are four components to dialogue (CoD):
• words that are spoken
• attribution—so your readers don’t forget who’s talking
• stage action—action, expression, and body language
• internalization—thoughts and feelings
Too often it’s just the words that are spoken and the other parts of dialogue are forgotten. I seem to remember a “rule of three” about not having more than three sentences of a person speaking before it’s broken up by another bit of something.
Nothing should occur in a vacuum.
Nullius in Verba 
I don’t read Joanna Trollope, but have listened to her books being read on the radio.
She has a habit of writing one line of dialogue, then one bit of stage action. Once you have noticed this, it’s seriously irritating.
So I think one has to avoid being formulaic about it.
We do like variety. Do we not?
Shouldn’t sucking occur in a vacuum?
And perhaps a bit of swirling, if the vacuum in question is a Dyson.
You’ve got me there, Plum.
Perhaps, I should have said, “nothing in a story should occur in a vacuum.