I have the same problem, I find it very hard to post. ^^"

I'm the opposite. I tend to get in there and post in threads where I have no business xD
I couldn't lurk if I tried. It's too temping to throw my two cents in everything.

I have my days when I know that communicating with others is going to be difficult because all I feel like doing is lurking, But I force myself to get out there and talk with people, since I know I have friends on here and I want them to know I still care XD
Its more than that though, I want to be there to help people, even on my down days because you never know if what you say could brighten someone else's day, and so, I still talk even when I don't want to because making people happy is worth it XD