I was so frustrated with him. “I just want to be enough for you, but I never can be. This can never be enough for you. But this is all you get. You get me, and your family, and this world. This is your life. I’m sorry if it sucks. But you’re not going to be the first man on Mars, and you’re not going to be an NBA star, and you’re not going to hunt Nazis. I mean, look at yourself, Gus.” - Hazel Grace to Augustus Waters.

Hazel was so frustated with Augustus. Because there was nothing that she could do to make him feel better, to make him be healthy again. Augustus was getting worse everyday, and Hazel spent everyday, every hour and minute that she could with him. She was trying to enjoy the most of Augustus while he was still there. Not really taking care of him, but she was his company.

 She saw him getting worse, and she knew what it was coming, as she was an expert on the subject, cancer. She looked at him, and she saw that he wasn't the same anymore. He was dying. And then, when they were together at his dining room with a friend of theirs, Issac, who just had an eye taken from him [because he had cancer, too], Hazel realised that, she was the healthiest person in the room, and I suppose that, in that moment, she felt really bad about the fact that Augustus was soon going to die.