It's about getting out of your head.
Think of it this way -- what's the worst that happens if someone shoots you down?
You say hi. They don't reply or they make a snarky comment. Conversation ends.
Or they say hi back. You say How are you? They ignore you. Conversation ends.
Or they say I'm good, how are you? You say you're good. Conversation stalls. Conversation ends.
Or the conversation continues.
Etc. Etc. What's the worst that could happen?
I'd suggest practicing somewhere where you don't have to worry about "embarrassing" yourself. Say, the grocery store, or when you're out walking your dog, or whatever.
Maybe you could even find someone to help you RP social situations. A shrink should be able to help you with this. Just be sure to tell them exactly what it is you want out of your sessions, or they'll find reasons to keep you going back
forever...
P.S. To actually answer your question, I may have been borderline a while ago. And then I just, you know, learned how to cope with and interact in social situations. The anxiety comes from feeling like this is a sphere beyond you. It's not. All it takes is practice.
That was a terrible reply. What is wrong with you? Good way to make someone feel like [censored]. Not very constructive, though.