^^;; Have been guilty of a few...I think #4 being the main one. And I agree with what you wrote about #5 *claws at eyes*

I don't even know what "l33+" means! -_-;; But, like Haunty and Ysa, I don't mind brb, lol, etc, especially since I use it all the time, but the alternating caps and numbers/letters drive me nuts! >.