It was the same thing in Britain when Princess Diana died - there was this "massive outpouring of public grief" that seemed to immerse the entire nation and after a while it did my head in.
Don't get me wrong, the 9-11 tragedy was a seismic event in world history and hopefully will never be repeated but you can't go flogging a dead horse like this. We need to eradicate the evil that goes on in the world which caused the attacks in the first place and I'm pretty sure the Bush administration's foreign policy was partly to blame for this. But that's another story. you could talk about it all night.