These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Adding to this is the fact that Adam never told her that he loved her, despite the fact that they were close enough to live together. Selfish as it was, could her cheating on him be a cry for attention from a neglected partner?
Award Snub: Joseph Gordon-Levitt's performance will make you cry, with no Oscar nomination to show for it.
The screenplay as well could've gotten in...but it DIDN'T!
When Adam hears of Mitch's death, he goes into a deep depression, thinking he won't survive.
Adam's breakdown while driving Kyle's car the night before his surgery.
The entire scene from when Adam tells his Alzheimer's-ridden father he loves him to when Kyle is standing outside the hospital.
The volcano story that Adam had been working on was already broadcast on the news before he could finish it. When you combine that with the cancer and his girlfriend cheating on him, it's not hard to imagine that Adam feels the whole world is pushing him out of existence.
The Woobie: Adam, and probably Katie at times with the way he responds to her therapy. Also Adam's mom may count.