The most tiresome, I thought, was the scene at the end with the Architect.

This was definitely the point my head exploded; I must admit I didn't follow the conversation well enough to get it all. In fact of the three others I was with, only one of us really followed the whole thing. To be sure, I think that was the intended effect. Anyway, I ended up finding the transcript of the Architect scene on a website which helped me understand everything. This didn't make the movie tiresome for me, just that much more interesting. Of course they could mess it all up in the next one if it doesn't turn out cool.