I've only had a few dogs in my life, so I'm not sure if this is true for all them, but my boys have their favorite "spot" to lay. During the day, they have their spots. In the bedroom, they have their spots. I guess we are all that way - we have a comfort zone that we like to stay within. I know I like to sit in the same spot on the couch - and now that cushion is a little flatter than the others!!! LOL
I've noticed that Hoss like to nest. Blankets, beds - whatever he can get his paws on. Whenever I do laundry, Hoss is right there. He thinks my sorted piles of clothes are little nests for him. He holds nothing back, and plops right down in the middle. I suppose it is okay - the clothes are already dirty. My only issue is when he starts "fluffing" and messes up my sorted piles!!!