Ha, ever since I was in 5th grade I've had sort of a poker-face. Always got called out for not being enthusiastic etc. In High school I was always tired so my eyes were constantly red, Literally everyone but my close friends thought I was a stoner. My teachers automatically disliked me and some classmates didn't want to associate themselves with me. I have never smoked in my life.

Now in university I've lost the red eyes but I've still got the serious looking face and expressions. I know for a fact I'm kind of intimidating to my peers despite the fact I'm not a huge guy, nor am I ugly. As for smiling, a lot of the times I think I'm smiling it turns out I'm not. My yearbook photos will show that to you.

So in short, yes it makes you a little unapproachable. Not gonna sugar coat it, it is how it is. Just accept it, and no need to try to change what is natural.