Grayson’s review published on Letterboxd:
There's a moment early in this movie where Llewyn Davis's sister tries to give him some early recordings from his childhood. Llewyn tells her to throw them out and says, "You're not supposed to let your practice shit out. It ruins the mystique."
It's one of the movie's funnier lines, and I think is also one of the movie's main themes. The movie's next immediate scenes follow Llewyn as he gets an unexpected invitation to a recording studio. We watch as he sits down in a studio and learns a new song. In other words, we get a close look at the "practice shit" that isn't supposed to be let out.
The whole movie is, in various ways, ruining Llewyn's mystique. His music career is dead and presumably over. His friends and associates are aging squares, all of them either out-of-touch with the music scene or slowly exiting. Llewyn Davis is not necessarily a smart or wise or likable person. The movie even invites us to question his talent by drawing an impossible comparison between Llewyn Davis and Bob Dylan.
Llewyn is not someone who necessarily deserves success. It's hard to disagree with Bud Grossman when he says, "I don't see a lot of money here."
But as much as the movie is honest about Llewyn's life, it is also sympathetic. He's still a human being, one who's just trying to make rent doing something he's good at, that other people enjoy. There is no high-minded myth-making here. (You could consider this film the opposite of I'm Not There.) Llewyn's greatest frustrations involve trying to fulfill his obligations to friends and family. Llewyn may not deserve success, but he certainly does not deserve miserable failure.
I enjoy this movie for a lot of reasons: the music, the performances, the humor. (The cat acting.) But I think this film is most effective as an observation of the simple tragedy of Llewyn's life. He's trying to make a living with folk music, something of unquestionable value to our culture, just not the kind of value that puts food on your table.