“I'm a soldier, but in serving my country, I have betrayed my conscience.”

Tom Cruise - Colonel Claus von Stauffenberg

You go around like an open nerve saying, "Oh, yes, I'm cheating... but look how guilty I feel! So, I must really be a nice guy". Then... then to top it all, you have the incredible arrogance of thinking you're the only person in the world with a conscience! That doesn't make you a nice guy, George! You know what that makes you? A horse's ass!
Ellen Burstyn - Doris

“- Lieutenant Colonel Frank Slade: Haven't you heard? Conscience is dead.
- Charlie Simms: No, I haven't heard.
- Lieutenant Colonel Frank Slade: Well, then, take the fuckin' wax outta your ears! Grow up! It's fuck your buddy, cheat on your wife, call your mother on Mother's Day! Charlie, it's all shit.”
Al Pacino - Lieutenant Colonel Frank Slade
Chris O'Donnell - Charlie Simms

“- Dory: Who's that?
- Marlin: Who's that? Who else would it be? It's me!
- Dory: Are... are you my conscience?
- Marlin: Yes, I'm your conscience. We haven't spoken for a while. How are you?
- Dory: Eh, can't complain.
- Marlin: Good. Now, Dory, do you see anything?
- Dory: Yes, I see... a light. Hey, conscience, am I dead?”

Ellen Lee DeGeneres - Dory
Albert Brooks - Marlin

“That little voice in the back of your head right now, it's not conscience, it's fear.”
Ben Affleck - Ivan Block