1. When Crowley asks Sam if he missed him and sad, broken, battered Sam pulls the demon blade out (flashing some skin even) and quietly says "So much."
2. When Dean tells Sam "I'm doing all I can not to come over there and rip your throat out. With my teeth."
2b. The way his tongue rests behind his teeth right after he says that. He does it in Soul Survivor too. It kills me dead.
3. When Dean asks if Sam really thinks those handcuffs are going to work, and Sam (again quiet and broken but not giving up) says "There's one way to find out."
4. At the end, in the car, when Sam is clearly feeling relieved and hopeful, and Dean yanks that rug right out from under him, and Sam does the jaw thing.
I mean, DAMN.
Honorable mention: mocking the puppy dog eyes, taunting Angry Little Cole, your tiniest umbrella, "what I'm gonna do to you Sammy," Sam's hurt reaction to everything, the single upraised finger and "you don't have to do this..."
Soul Survivor is up next. This sick day might just be the end of me.