Social anxiety is a lot like stage fright.
It is a crippling fear of being judged and/or messing up horribly.
You go over your lines and actions thousands of times in your head before you go in front of people, but you can’t get rid of your stomach butterflies and still freeze up when you’re on the spot.
You know that the fear is unreasonable and you’ll probably be fine, but you just can’t get over it.
Knowing that all the attention will be placed on you, the newcomer, makes you want to throw up.
So the only real difference between stage fright and social anxiety is that one is “fake”