Besides the many, many moments mentioned already, there's one wordless scene that just kills me. At the end of the flashback scene when Jack is sleeping on his feet, Ennis rides off and Jack watches him go. Cut to Ennis driving away after their confrontation and Jack watches him again, such a different look.
All the emotions in Jack's face in both those scenes, it just wrenches my guts and heart everytime. Probably being 39 now has something to do with it, but it's...ugh, I can't even explain it. But that's the moment for me.
Juan