Or the reason your readers will be skimming the page. Don’t tell the readers things they don’t need to know. If they don’t need to know them – they don’t want to know them.
The reader wants to reach the ‘pay off’ portion of the scene and they will grow irritated if they have to wait around while the author gives them unnecessary information that only stalls them from getting to what they’re reading for.
Supporting details only.
Yes, sometimes it’s hard to get rid of a beautiful setting description or a momentary exchange of dialogue that is character revealing, but brings the plot to a stand stilling. I’m currently revising my manuscript and editing out unnecessary details is next on the to-do list.