oh boy am I glad I finally saw this thread. I am responding to your original post, bar.
I have grappled with this thing for what seems like my entire life. I mean the following in the best way possible: I'm very glad to see that you are close to my age.
It also makes me feel better to see that you are highly intelligent. I don't mean to say that that's one of my traits. I'll try to explain, and I warn you, all the following is pretty much all about me:
I have always been concerned about my level of intelligence (is it enough), my sense of humor (or more often what seems like a lack of), and not being able to partake in the banter that seems to be a large part of day to day socializing that most people engage in.
I've always been of the mind that a person needs a nimble intellect in order to be funny....... I don't know what I'm trying to say now. I've had some Guinness.
I guess what I'm trying to say is, I have always been bothered by this very same thing.
All I know for sure is that the anxiety gets in the way of your natural thought process. It's a vicious cycle of anxiousness, thoughts, resulting behavior, which leads to self criticism which leads to anxiousness, and the whole thing starts over again. CBT is about breaking that cycle at any point, so once you've practiced it so it's like second nature, you'll have broken that cycle and you'll be able to think clearly when in a conversation.
I guess the most important thing (to me) that I'm trying to say is, I'm so relieved to read your post. I mean, I know I'm no PhD, but I'm also not stupid. Just, thanks for writing about the situation so well.