Often I have not-completely-satisfying sleep when I have my windows open. Sleep with open windows was more satisfying this time than before. Thank goodness.
I didn't leave open the window right next to my bed. I don't like my head being that exposed. It's psychological, though: I'm just as close to the outside whether that window's open or closed. If I had a burgler or a stalker outside that window, they'd still be hella close. It's that "tiny pane of glass" (quoting Pearls Before Swine there!) that provides some, I guess, psychological insulation.
But now that I'm awake, that window (one of my biggest windows, by the way) is open and letting in breeze. This relieves me.