Speaking of Tom's face: --The utter distaste he shows when Moe Greene blows into the hotel room with his "greetings." --The patented Robert Duvall grin when Tom is listening to Sonny banging Lucy.
A bit different from the book:
Out in the garden, Hagen searched anxiously for Sonny Corleone. He told the waiting Bonasera to be patient and went over to Michael Corleone and his girl friend. “Did you see Sonny around?†he asked. Michael shook his head. Damn, Hagen thought, if Sonny was screwing the maid of honor all this time there was going to be a mess of trouble. His wife, the young girl’s family; it could be a disaster. Anxiously he hurried to the entrance through which he had seen Sonny disappear almost a half hour ago.
