This is yet another problem I have struggled (maybe others can relate.) You try to go out to public places (retail, restaurants, etc.) and the objective is to socialize with a stranger.  The problem is when you realize there is an opportunity, you just immediately fumbled the football.
This problem can be one or more of the following:

• You were trained as a child, and in your late teens to not talk to strangers
• You were told to not give out your number, as some girls/guys could consider it stalking
• You are insecure of yourself
• You are afraid to divulge too much  information
• You are afraid to damage such low level relationship

This has happened on several occasions within the last 3 months. One was at the local fast foot joint, where I have a “fake” ID badge.  Its not that fake, I had a IT services operation and while it wasn’t incorporated legally, but I wear it with an accompanied lanyard  to look like I was “busy”. But I didn’t take the business seriously for reasons not worth going. The guy asked me how was “work”? I fibbed and said “good”. For all I know, he was just doing his own personal SOP of being nice to the customers.
Another case was I went to a mall store around the time when the Boston Bruins was in the Stanley Cup, so sometime within the last month. I was wearing my Bruins hat, and the girl at  this store was complementing me about my hat, while I was in the store she essentially was flirting with me and asking me if I was excited about the series. I came off like I was a “casual fan” when in fact I am a true fan. For all I could say in return in complete sentences was that I told her I liked her belt she was wearing and how sexy it looked.
And most recently, a cashier at the local grocery store had shown interest in me. No, not romance or crushes, but just an acknowledgement in a friendly way of my presence. (If you know what I mean, you understand what I had to deal with for many years.) The last time I saw her was about a few weeks ago, because I have missed her on her shifts in the last 3 weeks. Its rare for a grocery store let alone the Northeast where someone is friendly with their customers and not rush to put the pizza in the same bag as the chicken. The problem is how can I go that next step into the “small talk”. I’m not like an Asperger type where I hate it, its really how to execute it, and how could I ask her out (if that’s even possible.)
I seem to never find the right time to act when I have an opportunity to interact with the outside world without having much fear. The problem for me is how chronic this social anxiety almost literally  freezes me up without getting cold hands or feet.
I think it comes from my upbringing of low self esteem, a lack of confidence of my professional interactions, and just the baggage of carrying my autism and all the negativity that the disorder has been wrongfully portrayed in the public.