I live in Atlanta. The thing you need to understand is that this is a TERRIBLE city for pro sports. College football dominates everything here. The hawks are fighting for the number 2 seed and yet all the sports stations talk about is national signing day, lane kiffin, mark richt, the new UGA defensive coordinator, etc.
So in 08 to drum up some interest after that playoff series the hawks started doing a "rivalry night" when the celtics were in town. Of course, the celtics never took that gimmick seriously, so now they are madder than ever.
I sometimes post on a hawks message board that I started posting in order to get info on going to Phillips arena and so on. People there are seriously upset that the celtics don't consider this to be a rivalry. They don't care about the magic or the cavs, they want to know if the celtics think of them as a rival. I guess when you haven't won anything, you have to build yourself up by creating some fake rivalry.