I think the whole silent exchange at Mama Corleone's wake, between Michael and Neri, was particularly moving.
You can actually see Al show some humanity by lowering his eyes, as if to say, "I'll do it, but it's really a shame you have to do this to your own brother."
I had a friend who, back in the 70s, mentioned that same Neri look. At the time I didn't agree, but now I do.
