I can't switch sides. When I do (when Deb & I are traveling — switching at home would involve swapping 25 years of Stuff from one side to the other, including six drawers of under-bed storage) I get a frantic wake-up in the middle of the night from my "hind brain" — the part of my brain that keeps track of stuff when I sleep. It deals with simple stuff pretty well; I can wake up with my blanket over me because hind-brain knows how to do that without waking me. It also handles strange sounds ("If you hear rain, wake me up so I can shut the windows") and miscellaneous items like, Deb is on the other side of the bed so stay on your side.

So for whatever reason we decided that I would sleep on the right side of the bed at some hotel. I wake up around midnight, heart pounding, because hind-brain says Something Is Very Wrong. WTF? "There's someone in bed with us!" Yeah, it's fine, it's Deb, I'm going back to sleep. Then 2AM: "There's someone in bed with us!" Still Deb, STFU. 4AM: "There's someone—" #*@&$!

We swapped sides the next night. It was just easier then retraining hind-brain. <sigh>