I have always been a bed hog. When left to my own devices, I sleep diagonally or even across the bed sideways. Lori keeps me in check and usually on my left side, facing away from her so the snoring is slightly less locomotive-like. However, if, nay, WHEN I go to bed early, I'm sure I spread out and need to be moved. I know when I'm traveling for work, I revert to old habits and take up the whole bed again.
Some years ago, probably about the time we got married, I got switched from the left side to the right side of the bed. I don't know exactly how it happened, but what probably started as a whim so I could be near the fan has become permanent. I suppose I don't mind this, but that might have something or another to do with why I gravitate back to the other side of the bed when left unchecked.
A cursory search of the Internet shows studies to determine if you sleep better on one side versus the other (right versus left, not top versus bottom), or if it matters in a relationship, which seems to dictate that the man sleeps closest to the door, which I usually do by virtue of the room design. There's no feng shui of bed side that I can find. I don't even understand the feng shui diagrams available on Google, though admittedly I didn't try very hard.
How about you, dear reader? Do you have a preference of side? Does the person with whom you share a bed have a side preference, thereby relegating you to the other side by default? Do you sleep on a side when you're alone?