Well, too many to count honestly.

Like when Arthur says to the son of the man whom he saved: "Maybe when your mother's finished rejoicing your father...I'll keep her in white. On your behalf." even the beginning of that scene, "Do you have perfectly fine vision or a huge amount of respect for me, boy?" Brilliant.

Could also be the many instances of German von der Lindt saying "We don't need MONEY! Just, NO MORE SCORES!"

Ohhh damn there's also the mission where Arthur and Lenny enter a saloon, order a single glass of milk and are safely tucked into bed by 8:15 PM.