The first conversation, from "Swords and Deviltry":
Fafhrd and the Gray Mouser faced each other across the two thieves sprawled senseless. They were poised for attack, yet for the moment neither moved.
Each discerned something inexplicably familiar in the other.
Fafhrd said, "Our motives for being here seem identical."
"Seem? Surely must be!" the Mouser answered curtly, fiercely eyeing this potential new foe, who was taller by a head than the tall thief.
"I said, 'Seem? Surely must be!'"
"How civilized of you!" Fafhrd commented in pleased tones.
"Civilized?" the Mouser demanded, suspiciously gripping his dirk tighter.
"To care, in the eye of action, exactly what's said," Fafhrd explained. Without letting the Mouser out of his vision, he glanced down. His gaze traveled from the belt and pouch of one fallen thief to those of the other. Then he looked up at the Mouser with a broad, ingenuous smile.
"Sixty-sixty?" he suggested.
The titles in this series are, in order of character aging:
Swords and deviltry
Swords against death
Swords in the mist
Swords against wizardry
The swords of Lankhmar
Swords and ice magic
The knight and knave of swords
There's also an excellent graphic adaptation of several of the stories, written by Howard Chaykin and drawn by Mike Mignola.