An interesting issue is that humans perceive the world in all colours and the angels perceive it in black and white. This choice has both negative and positive point, and given that only one other choice exists, not a lot can be said about this. I firmly believe a lot of art is done for reasons only an artist can comprehend. While analysis of art is a reasonable thing to do, discussing the analysis with the artist somehow seems comical to me. This is illustrated by the ironic fact that in the movie itself there's an artist and people comment about how great his work is, and his style of art, and the artist is thinking that he really has no idea what he's doing, and neither do the people who admire his work.
Time is the absence of money.
There were a lot of other good ones, but I forget, since the subtitles flew quite fast and the short-term memory isn't good enough to hold it all.