A bathroom doesn't have to be just that - you can add plenty of furnishings in it to create a luxurious atmosphere, as long as you have the room. If you've ever been to a spa or if you've stayed in a fancy hotel, you'll notice things that you'd think shouldn't be in there, but it works! For an available corner in your bathroom, why not add a seating area where you can lounge around just like you would in a spa?
For a luxurious feel in your bathroom, add a lounge chair or a chaise by a beautiful window or a giant ottoman in the middle of the room. For that nook, you can even get a side table to display some bathroom accessories or a potted plant.
Do remember to purchase a piece that will compliment your existing fixtures like your bathroom vanity. Additionally, opt for a fabric that will be resistant to the changing conditions in the space - a leather chair, for example, may not be ideal in a humid bathroom.