I think my introversion and extraversion tends to vary based on the subject/activity/audience. If I'm familiar with a situation or group then I'm a lot more extraverted, even taking leadership positions, if its a random dance club...I'd rather just stay at home with a book.

However, I must respectfully question your premise about the camera being a shield in street photography. I often end up worrying that the random person I was photographing on the street will get angry or weirded out by the camera.

I'm worried they'll come up to me and ask me questions when I wasn't (as an introvert in public) really prepared to talk to someone, let alone someone who's mad I took their photo across the street.

How do you deal with that aprehnsion when you're shooting people?