The thing with 'am i rite' is you can, almost in every post it is used in, replace it with the rolling eye smiley and you have essentially the same effect. It is just a written form of it. I don't see what is particularly annoying about it.
I just, probably idiotically, assume that when someone here says something that it originated here because I rarely go to other sites that people talk about, and when I do, I usually only spend about 10 minutes there and don't go back. I think I am giving the people here too much credit.
![Very Happy :D](./images/smilies/icon_biggrin.gif)