I think there is a life cycle. A user starts fresh and new, and then tentatively puts forth a comment or submission. If the comment or submission isn't immediately lauded, I think the user my temporarily become snarky and/or bitter. Then I think they come around again and more maturely interact.

Maybe you have to have wait 30 days after registration before you can comment? Or comments within 30 days of registration have special "new user" formatting?