- Groucho's favorite line in the film was, "Remember, you're fighting for this woman's honor, which is probably more than she ever did!"
- On a meta level, Margaret Dumont (who was on the receiving end of the line) had no idea what Groucho meant. When she asked for an explanation, the others immediately jumped at the opportunity to explain it by assaulting her, in good humor of course.
- The mirror sequence is the funniest scene ever put to celluloid. There, I said it.
- The trial.
Rufus: Look at Chicolini. He sits there alone, an abject figure—Chicolini: I abject!
- During Chicolini's trial (which was full of objections, from both sides):
- "To War!"
- The encounter with the lemonade vendor.
Vendor: I'll teach you to kick me!Chicolini: You don't have to teach me, I know how!(to prove his point, he kicks him)
- Especially this exchange:
- Both times Firefly gets the ambassador to call him an upstart.
- The motorcycle and sidecar running gag. The first two times Groucho gets in 'his Excellency's car!', his drive Harpo would go off, leaving the sidecar behind. The third time, Groucho gets wise. ("Oh no. You can only fool a Firefly twice. This time you get in the sidecar.") While the motorcycle remains still, Harpo in the sidecar rides off.
Rufus T. Firefly: This is the only way to travel.
- The whole bit where Groucho makes Chico Secretary of War, from start ("You want to be a public nuisance?" "Sure! How much does the job pay?") to end with Harpo showing off his tattoos to Groucho. ("Well, I know one thing. I bet you don't have a picture of my grandfather." Harpo starts to remove clothes.)
- Chicolini and Pinky's introduction. To show Trentino what brilliant spies they are, they walk into his office wearing ridiculous-looking Paper Thin Disguises—Pinky even walks in backwards, wearing a fake beard and a pair of hypno-glasses on the back of his head. Trentino just stares at them dumbfounded. Then they throw off their disguises, and Chicolini proudly yells, "We fool you good, eh?"
- Trentino gets a telegram - Pinky intercepts it, looks it over, furiously wads it up and throws it to the floor. Chicolini: "He gets mad 'cause he can't read!"
- The first conversation Rufus has with Mrs. Teasdale:
Mrs. Teasdale: The future of Fredonia rests upon your shoulders. Promise me you'll follow in the footsteps of my husband.Rufus: (aside to the camera) How do you like that? I haven't been on the job five minutes and already she's making advances to me. (to Mrs. Teasdale) Not that I care, but where is your husband?Mrs. Teasdale: (sadly) Why, he's dead.Rufus: I'll bet he's just using that as an excuse.Mrs. Teasdale: I was with him until the very end.Rufus: No wonder he passed away.Mrs. Teasdale: I held him in my arms and kissed him.Rufus: Oh I see, then it was murder! Will you marry me? Did he leave you any money? Answer the second question first.Mrs. Teasdale: He left me his entire fortune!Rufus: (suddenly friendly) Is that so? Can't you see what I'm trying to tell you, I love you!
- When Freedonia is bombed, Groucho manages to get a giant vase stuck over his head. Harpo's idea of helping is to draw Groucho's face on the outside of the vase.
Rufus: (post-explosion) Any mail for me while I was gone?
- When Chico is asked to go out into the war zone:
Chicolini: I wouldn't go out there unless I was in one of those big iron things, go up and down like this... What do you call-a those things?Rufus: Tanks.Chicolini: You're welcome!
- "JOIN THE ARMY AND SEE THE NAVY"
- During the firefight with the enemy army, Rufus accidentally throws his rifle out of the window.
Rufus: There goes my gun (turns to Mrs. Teasdale) Why don't you go out and fetch it like a good girl.
- Rufus' immortal "idiot" line: "Gentlemen, Chicolini here may talk like an idiot and look like an idiot. But don't let that fool you. He really is an idiot."
Funny / Duck Soup
Let's not kid ourselves — this is the Marx Brothers we're talking about. They could do your taxes and it'd be hilarious. The whole damn movie is one long Crowning Moment Of Funny from five minutes in when Firefly first enters to the fadeout at the end.