You have hit a nerve with me on this one.
It makes me soooo mad, to be told to smile.
If someone would say that....I would just look at them in disgust.Make them 'think', before saying it again.
What if someone just lost a loved one.Or lost their job, or house....whatever, we have no right to expect a smile.Even if all is well with their lives, some people are just serious.I for one am, and sometimes we don't want to smile.
Our world has many complications, more than any other time...and we do have weight on our shoulders.
I wouldn't think it sexist.......but rude, absolutely.