Dont know if its really that subtle..but Vito's face when Luca repeats "on the day of your daughters wedding".Just the expression on Brando's face makes me smile everytime

The hero and the coward both feel the same thing, but the hero uses his fear, projects it onto his opponent, while the coward runs. It's the same thing, fear, but it's what you do with it that matters. Cus D'Amato