I suppose that is true, but seriously I am now reading the light novel series of Suzumiya Haruhi and learning quite a bit about what the hell was going on in the series.
The anime itself was amazing it was 99.9% intune with the light novel.
But my main reference to this is the second novel "The Sighs of Suzumiya Haruhi" in which the novel focused on the making of the movie they did. Reading it I finally understood wtf was going on in some of the scenes of the anime.
That point where Nagato tackled down Asahina and the talking cat as well as some other things were explained. (wont say because it would spoil it)
Hopefully the second season will follow up on this.
The only difference with the novel and the anime was that Haruhi never played the guitar during the festival, she had Nagato do it while she just strictly sung and they did 4 songs