I think stuttering killed my extrovertedness. It's not easy being a bright eyed kid wanting to say something and having someone else tell you to "spit it out" or "what, forgot your name?" I've even been flat out ignored. You may have friends, but it feels like you're just around and not really a part of anything a lot of the time. Comments often get brushed aside if you can't get it out. That kind of killed it for me when I was younger. Around 12 I just started talking a lot less. I found that adults tend to be less rude about it, because civility is valued, but the damage has been done. I'm generally much more reserved now and I think the lack of practice has kind of made my social skills rusty, which reinforces the shyness even more. Even thinking of talking gives me an anxiety in a lot of cases. It's mentally exhausting.