I made it halfway through. Not only is it a very slow slice-of-life film, the main character (Michael Cera's Eric) is so repellent, I just didn't want to spend any more time with him. He is inconsiderate, self-absorbed, cold, oblivious, and shallow. He blows off all these people who made plans to spend time with him in his rare visit, with barely a 'sorry.' Both of his sisters are obviously suffering, and he doesn't even seem to notice, let alone care. He even scolds the one who adores him. At one point, he shows what really matters to him (and it's not anyone else), and asks her why the other sister 'hates him.' The short answer is that he is just a JERK. The real question is why there is anyone in his life who actually tolerates him.
Review of The Adults
