GG is that sexy girl you dated in HS that was kind of shallow, sort of an airhead, and you knew it wouldn't work out after spending a bit of time with her. It seems like a lot of people think back to the days with her, because she was so sexy, and want to give it another shot. If we realized we didn't like her then, we're still going to be dissapointed if we go back to her. (and yes this is based on experience)
(for the female cb'ers (not sure who you are, show yourselves) pretend its a guy, maybe a meathead instead of an airhead, same principle applies)