It's interesting how much of my aesthetic these lines imply:
I cannot rub the strangeness from my sight
I got from looking through a pane of glass
I skimmed this morning from the drinking trough
And held against the world of hoary grass.
It melted, and I let it fall and break.
(Frost, "After Apple-picking")
One doesn't value the pane because it's a means of escape from realism. If that were the point, then scifi and fantasy would be worthwhile, which (to my mind) they aren't. It's essential to have something utterly recognizable on the other side of the pane of glass. Another example --
Useless to think you'll park and capture it
More thoroughly. You are neither here nor there,
A hurry through which known and strange things pass
As big soft buffetings come at the car sideways
And catch the heart off guard and blow it open.
(Seamus Heaney, "Postscript")
I wouldn't care much for this except that the last line makes me think of a plastic bag in the wind.