After reading through some threads, most posters are lovely, kind and helpful. However, there is sometimes this thing where when poster criticises the OP and all of a sudden most posters also gang up on him /her.
I've seen so many people told, "You need professional help." as opposed to suggesting that someone may find therapy helpful. Telling a stranger they 'need professional help' is out of order.
"You've posted before !!" Because apparently nothing can ever happen more than once. It's also not a crime to post more than once if people feel they want further help or advice.
Talking about the OP as if he/she isn't there. "She posted that 1 week ago" etc.
"You sound like a needy 14 year old".
I think sometimes it just goes a bit too far.