I used to have an “awkward smile” as in I couldn’t help but having an ear to ear shit eating grin whenever I was uncomfortable or upset. It would then perpetuate itself when I was conscious about it and uncomfortable at the fact that I was smiling at an inappropriate time. Took some practice at keeping a poker face initially. Once you can keep a straight face in any situation it’s much easier to fake an appearance. Still exhausting emotionally faking it.