I write in my home office that doubles as a guest room (thank goodness we don't have many guests), a TV room and a place to dump the laundry.
The room contains a desk with a computer, a low chair (I cut down the legs of the desk to deal with this), two windows, a wall of book shelves, my kids’ artwork, a concrete statue of a dryad, my father-in-law's mother's fold-up wooden rocker where she breastfed six children and several resident spiders.
I sometimes write with a hoodie over my head, especially if one of the spiders has walked to the part of the ceiling directly above my desk. Somehow this has the effect of making me crouch low, lean in and get down to writing.
I'm no good writing anywhere else. I don't need silence, or a closed door, or a disconnected Internet, but I do need one consistent, unchanging place to sit myself down. In order to write, I basically have to get my ass in that chair.