I found the movie so frustrating, I had to turn it off after about 20 minutes. Examples:

High-school-level conversation about insanity between two people who are both supposed to be exceptional mathematicians.

Ridiculous back-and-forth between Gwyneth Paltrow and Jake Gyllenhaal where they keep changing attitudes and even personalities. I know it's based on a stage play, but couldn't they calm it down a bit for the screen?

Lazy screenplay shorthand for bossy woman: talking on cell phone about china patterns while walking through airport. Grrrr!

And finally, what made me shut it off: That insane conversation between Paltrow and Hope Davis, where one thinks the other is hallucinating for no apparent reason.