This is my experience of having social anxiety. Imagine you're worst fear is playing the guitar in front of people and appearing to suck at it. So you practice really hard and get good at playing the guitar. But then when you go to play it for some people, you get so nervous that your hands shake and it makes you suck - your worst fear coming true. It makes you feel terrible. So, you try again, but this time you're even more nervous because of the way last time went, and your hands shake even more, and you suck even worse, and people respond even more harshly. And so on and so on. This is why it isn't just a matter of developing social skills or confronting your fears.