- Felix Unger: I don't like to see my friends fail.
- Oscar Madison: Felix, everybody fails. Caesar failed, Napoleon failed, Alexander the Great failed.
- Felix Unger: They weren't my friends.
- Oscar Madison: They were lucky.
- Felix Unger: I've never seen you like this. So low, so depressed, so defeated.
- Oscar Madison: Weren't you at my wedding?
- Officer Murray Greshler: What's Oscar's book about?
- Felix Unger: Sports, of course. It examines the question of the killer instinct in champions. Why does one man, with all the natural ability in the world, why is he a mild, passive man, while another man, with only the same ability, has that savage desire to smash, to kill, to fight, to destroy? What makes that killer instinct?
- Officer Murray Greshler: I was born with it.
- Felix Unger: [despite an all-night session working on his book, Oscar has only written the title] This is all you wrote? A title?
- Oscar Madison: A title is very important. Would you go see a play called 'Romeo and Gladys'?
- Oscar Madison: [explaining that he can't write his book] Felix, why don't you listen: I can't write it.
- Felix Unger: Can't! That's not the Oscar Madison I know. My Oscar Madison doesn't know the meaning of the word 'can't'.
- Oscar Madison: What are you talkin' about? 'Can't' is my favorite word. I use it all the time: "I can't write the book; I can't pay back the money; I can't win on the horses." When I die, on my tombstone it's gonna say, "Here Lies Oscar Madison - Couldn't".