I used to experience this as well, I always worry whether my reply will be right or not and rewrite my messages tons of times. What helped me was thinking from a different viewpoint, such as: when I post threads do I look for replies I think are wrong? Nope, I don't think any replies to my threads are wrong, I appreciate all the replies I get so that's probably how the majority of other people feel as well, then I realize my fear was irrational.