Sort of. Some of us really respond terribly to criticism, but I found out something very odd about myself recently - criticism isn't the issue. It's the constant anticipation of criticism that gets me feeling so bad. When in reality, if somebody starts something with me, I usually have the strength and adrenaline to stick it through. In short, if you get me pissed enough, my shyness is rendered obsolete. Why? No idea!
I think it's just that constant flow of emotion. I'm the kind of person that needs to express it - and this could very well be true for any other shy or socially anxious person out there. I'm good at suppressing my feelings, however whenever I do I feel so dead inside. The more I let them flow outward - no matter if i'm happy, sad, excited, depressed, whatever - the better I feel overall, the more I connect to myself and the more I can connect with others.