1) The flashback scene at the end of Part II
2) Mike/Fredo "I know it was you, you broke my heart"
3) Vito/Tom "But you needed a drink first. And now you've had your drink"
4) Michael's face during the Sollozzo scene (the shooting)
5) Tom and Sonny arguing "...I didn't mean that, come on, I'm sorry, I didn't... Look it's Sunday, Ma made a little dinner..." "Forget it Sonny. Over."
6) Vito "Look how they massacred my boy"
7) Michael's reaction during the Superman scene
8) Mike calmly shutting the door in Kay's face
9) Mike's expression during the abortion scene
10) Mike "Don't ask me about my business!" when he snaps at the end of Part I and slams his hand down on the desk

I could go on, and on, and on...! lol

Just remembered:
11) Vito's speech at the Committee meeting "If he should hang himself in his jail cell. If he should be shot at by a police officer. If he is struck by a bolt of lightning . Then I am going to blame some of the people in this room."
12) Vito getting confused in the garden with Mike. Mike "I arranged that Pop, I took care of that already" while Vito mutters about phone calls. Then "Oh yeah, so you did, I forgot. I hope you don't mind how I keep going over this..."

Senator, we are both part of the same hypocrisy