If I don't do it now everybody else will beat me to it, but now I'm in fourth place and everybody else will be changing their avatars too late to be cool. Any moment now...
But whoever changes avatar next will be the 5th which is okay because somebody else will want to be 6th, and so on until we reach the nth user, if that user changes avatars s/he'll be the least cool user, so s/he won't if s/he's rational. Also if the n-1th user is rational, too, s/he'll know that the rational nth user won't change and know that changing will keep him/her in the least cool spot, so won't. Same goes for the n-2th, n-3th and so on until we get to the first user, so the rational course of action is to never change your avatar.
This is called the Bottle Imp Paradox, except it's not really a paradox because we already knew you're all irrational and uncool anyways.
For the record, I wasn't aware that All Nines had changed his avatar by the time that I changed mine. Though it was sort of because of the thread yeah.
Hats and tinsel do not the spirit of Christmas make. The true spirit of Christmas lies on the inside. At this very moment my blood has been replaced with eggnog and my bones with candycanes.