Once my grandmother took a short trip on which she hit a dog. Before I talked to her about her trip, relatives warned me that her story was expanding.
First, she hit a dog.
Then she hit the dog and he rolled and bumped under the car.
Then she hit the dog and he rolled and bumped under the car all the way through the town, making horrid howling whimpering sounds.
It only got worse from there.
So, in my family when someone is "dragging the dog," they are wildly exaggerating.
Steven King is one writer who uses private family language as a device to build realism and atmosphere. Private language takes us into a character's intimate environs. Private language tells us about the characters in a sly way, slipping in exposition of the character's history without trying our patience (at least one would hope so).
On the one hand, part of the way through a King book, one can almost "get in" on the conversations in the characters' private language. On the other hand, overuse of the device tries my patience. It may be that King does not overuse private language from the standpoint of realism. But realism should not get in the way of telling the story well.
But, on my third hand, am I really arrogant enough to say that Steven King makes mistakes? Yes, I guess I am. Even the masters can make mistakes--fewer and smaller mistakes than writers like me.
In any case, a bit of "dragging the dog" would deepen many stories.