On a forum it's hard to determine if a person really cares about what you post. It's harder to spot sarcasm, perhaps you think people aren't listening but it isn't always the truth. When you post something you expect someone will answer, reading that answer is hard when you can't see the other person's face.

I have deleted my account at several forums ( not related to SA) because I got responses to threads that made me feel bad. Sometimes I would post something stupid, other users who are much smarter than me (I'm guessing at least 90% of the world's population) ridiculed me and the only thing on my mind is to get rid of the place asap.
After some time the old demon that is low self esteem in me just pops up and makes my head spin. It happens every time.