I think we all start out cautiously when we join a forum. We're all afraid of making mistakes, even in spelling. I think most sites now include spell check in their software as a misspelled will appear with a red line under it. Even I make mistakes.
In time, you learn who you can kid around with.
When it comes to authors, that can be interesting. One author that I write to can be rough sometimes. I learned over time from his replies, and comments at another site, it's just his nature. For another author, I disagreed with him on something and we've had many a good discussion since about his story.