This door you might not open, and you did;
So enter now, and see for what slight thing
You are betrayed.... Here is no treasure hid,
No cauldron, no clear crystal mirroring
The sought-for truth, no heads of women slain
For greed like yours, no writhings of distress,
But only what you see.... Look yet again--
An empty room, cobwebbed and comfortless.
Yet this alone out of my life I kept
Unto myself, lest any know me quite;
And you did so profane me when you crept
Unto the threshold of this room to-night
That I must never more behold your face.
This now is yours. I seek another place.

Edna St. Vincent Millay

http://www.poemhunter.com/poem/sonnet-vi-this-door-you-might-not-open/