Imagining Grey Wind's head on Robb. When that was described I was so upset I didn't pick the book back up for a few days.
Catelyn's treatment of Jon.
Whenever Jon and Arya think of each other.
A couple that haven't been said:
When Jon finds Donal Noye and Mag the Mighty dead at the hands of each other, and then subsequently every time Jon remembers Donal.
When we find out Beric Dondarrion died his final death bring back Catelyn. I was more mad than sad. I liked Beric, not necessarily loved him, but I HATE Catelyn. The way she treats Jon, how she frees Jaime in hopes it will get back Sansa and Arya (which we as a reader know she won't get Arya), her vanity, and then after her resurrection how blindingly and ignorantly angry she is with Brienne and is ready to kill her and poor little Pod. UGH!
Catelyn Tully has been on my no-fly list since she told Jon Snow it should have been him. I was already irritated by her knowing the signs of danger (direwolf killed by a stag's antlers), and purposely twisting that obvious prophecy for her and Lysa's own ends.