I hate constantly trying to play up to people's expectations, and trying to fit an image. This applies in almost every walk of life, but don't get me started .
I feel you. What also annoys me is the complete obsession with not capitalizing the I's and the overexcessive use of periods. I explain it in my random rant here - http://forums.digitalpoint.com/showthread.php?t=1572350
It annoys me when people say they're earning $1000/day or whatever along with an affiliate link in their signature, but their behaviour with money tells quite a different story.
How could I forget that. I don't even notice the threads that say 'MAKE XXX$ A DAY' anymore. I've become blind to them.