I think everyone has some situations where a little social anxiety creeps in. I don't like going to unfamiliar variety stores/gas stations/grocery stores. It stresses me out not knowing where things are - I prefer to stick to my usual locations and not branch out from there. Then there's eating alone in public. I have often eaten something in my car because I don't like eating alone in public. Again, I think it's a pretty common anxiety.
You know where it doesn't bother me to eat alone though?
The food court.
One day, Jenn and I slipped over to the food court to get some snacks to smuggle into a movie. As we stood there, shoving paper bags of tacos into our purses we commented on how anything goes in a food court. You can eat by yourself and it's not weird. You can order bizarre combinations of food and no one cares. Poutine and sushi? Totally do-able in the food court. People will set up camp to study or just kill time and no one bats an eye. It's a magical, wonderful wasteland of social rules.
Furthermore, if you're to believe Mallrats (and really, why would you doubt anything that happens in that movie?) it's also totally acceptable to carry around a Dixie cup to be refilled with Coke, no ice.
Nothing cuter than the young Jason Lee.