Too much of that wordless touchy-feely bonding between them, when Krasinski seemed like the kind of macho a-hole that would get offended at Cooper hanging around his ex and start a fight. Can just see them tumbling over the kitchen table while McAdams covers her face in shock; would've been nice balance to all the new age babble as well.
I actually like the dynamic between them. At first I was confused why he won't be angry that her ex was hanging around her in their home like that but as the movie went on, you realize that he was angry and he thought he will be fighting a losing battle if he intervened. The letter he wrote to McAdams really put it together - "I hated the way you change when Gilcrest came back to town, but I don't like to hate, it's bad for my brain.......I may not be the original owner of your heart, but I'm the better owner..."
What I thought that was missing in the movie was there could have been a bit of jealousy between McAdams and Emma Stone. Just a tiny bit.
Yeah, Emma's 'wide-eyed turn every time something she perceived as mystical occuring' schtick got a little one-note. A little jealousy of Cooper always hanging at McAdams would've been nice.