My natural facial expression is fairly serious, to the point that for a lot of my younger years I would constantly have people asking me why I looked mad or never smiled.

As I grew up I started learning to smile and laugh along with other people a lot more, but I think it is more of a supplication/rapport-building tactic than a normal, confident, socially appropriate amount of smiling and laughing.

As I've started to unplug in the past six months I've noticed that a lot of guys I meet who I am either impressed with or intimidated by seem to have a pretty serious, almost aggressive expression on their faces and don't smile or laugh nearly as much as I tend to.

Is this just a difference in personal style? Or is it something I should be paying attention to and learning to emulate?