What makes being "mysterious" attractive?
On another site, there was a debate about whether or not guys are more attractive if they smile or have a serious look on their face. The people who liked a serious look better said it looked "mysterious", which they find sexy.
As a woman myself, I have no idea what this "mysteriousness" is or what is so attractive about it. I've never really thought about it, myself, but it isn't a turn on or a turn off, I guess. If someone never smiles, I assume they are unfriendly and unapproachable, and don't want me to bother them, so I leave them alone.
So, what exactly does it mean for a guy to be mysterious and what is so attractive about it?