I'm told I don't smile a lot either. As hard as it is to do, its actually good advise. A lot of times we just focus on not having the courage to speak to people. But social anxiety is like a natural healthy "shyness in certain situations" gone overboard. Our body language tells people that we're closed off to them. Smiling and making eye contact is a part of being friendly with people.
I don't think it is enough, though. People recognize a forced uncomfortable smile. The hard part with social anxiety is that in social moments you're so uncomfortable that your mind is focused entirely inward. Smiles and eye contact seem to naturally come when we're enjoying someone else's company and what they're saying to us. When we don't smile or make eye contact, we're failing to show interest.
I think this is why in counciling, the focus on social anxiety deals so heavily with self esteem and positive thinking. You have to like yourself enough to stop thinking about yourself in order to be comfortable socially. I'm nervious around people because I'm looking for people to tell me I'm worthwhile and I'm afraid they'll tell me I'm not. In fact, they have told me I'm not.
The difference though is that everyone gets angry at everyone. There is no one person who is universally liked. Everyone has their opinion. To be able to approach strangers like
erfect: with sincerity involves being secure in who you are. Once you are, then you can forget about yourself and focus on the other person.
Easier said than done. I'm not there.