There's only one that I heard more than a few times, I don't even remember the first person who told me to..
I'm not sure how horrible I look not smiling. The worst I heard was "disgruntled".
I looked like my eyes just laser-ed through your skull when I'm not smiling, I was once told. But I was actually just staring into the blank. And I do that a lot. So now, once when I remembered to, I'll pull the corners up, and smile for no apparent reason.
Yup, just for the sake of smiling. Well, it makes me look friendlier and more approachable, I'm not sure if that's a good thing.
Any advice you wanna give me?