I'm a massive fan of Song for Dan Treacy. The organ is killer as a weird foil to the poppy foundation of the song. That said, Congratulations is far and away my favorite track. It's the only one that has a direct honesty to it, and it really gives context to the whole album. They were clearly struggling with the success they found with Oracular Spectacular. Congratulations, the album, was a response to that. The song itself reveals nuance to the whole thing - they're fighting against it, but drowning in the comfort of it. IMO, a perfect way to close out the album.