I understand how you feel.
I will refresh every 30 seconds, hoping that someone has posted.
I have learned to hate the online offline symbol with a passion too.
It looks so happy, while your ready to strangle the little smily, after 15 miuntes.
I however, don't become annoyed when I notice the person is offline for more than 3 minutes.
No point in getting annoyed with someone when they won't be back for a while.