The only time I received an unsolicited comment, was after I had a miss miscarriage ie my baby died in my womb and well, I am a smiler, but after that, I could not muster up enough energy to smile and one time, I was out side and this guy walked passed and said: hey, smile, life is not as bad as that!
I have always looked younger than my age and if anything, when I was commented on, it was always complimentary.
As for smiling whilst working. Well that is rather difficult for me, because I believe that if one is working in a public sector, they should smile, because it is welcoming!
I simply hate going to the supermarket and the teller is so sour faced that it makes me angry and I want to shout: do you think that not smiling is very friendly? Now, please bear in mind, that I do not say anything, because I am not that type of person. Of course, the teller could have had some dreadful news, but well, she (because it is normally a woman) is working in an environment where she is seeing many different people and hey, the person she is serving, could also have had some dreadful news.
So, basically when someone says smile; they are actually saying you are too pretty to not smile!
By the way, you are charming looking and personally you should not have to change your looks, if you are not offensive.
Unfortunately this world is not for sensitive people and I am the first to take things to heart and dwell over it and get more and more upset.
We are a strange lot because I like it when I am called cute lol