OK, I think I was finally able to figure out the order of screencaps here.
Grant tries to share something with Carter (see the post on "Momstrosity"), but Carter shoots him down. Grant's face goes through three stages - open and ready to share, disbelieving and hurt, and then hardened and angry. Beautiful.
I don't know how James Callis does this, but he does. Note the very subtle changes in his eyebrows and mouth, and the way his eyes change expression. It's hard to spot in still images, but I just had to make this its own post.