People often wonder why we are the way we are. The submissive businessman is said to be that way to balance his control at work with his need to switch off. Some say that submissives were abused as children and this is their way of coping. Dominant women are reacting to society's patriarchy. I think that you will find all these examples out there somewhere, but most of the people I know who are sub, dom, swingers or just a bit naughty share very little in common. Overall the sexual trait seems to be unconnected to any other aspect of their personalities.
Forget classifications, either you like having fun that way or not. Do we classify other pleasures? Do we ask why someone loves food, or another loves racing cars, or skiing?
I would say that the nearest thing to a common trait is the drive to enjoy life fully, but even that isnt across the board.