Oscar Isaac
When I started watching this movie, I had no idea who the lead actor was. He looked like a very cool Hispanic guy (and he was born in Guatemala, so that's what he is). But something about him kept bugging me... OH SNAP IT'S LLEWYN DAVIS! I hated that movie, too, and especially hated Oscar's character in that movie, so then all the negative feelings about Llewyn Davis came back and from that point forward, Oscar was just an actor standing in front of a camera, which is too bad because in another sense I thought he was doing a really good job. I just couldn't suspend disbelief and get back into the picture.
Overall, the picture was slow and boring anyway.