Watch closely when Harley jumps into The Joker's arms. As she turns her head, one of the balls on her jester's hat hits The Joker in the eye.
Gotham City has a population of about 10 million people according to Mayor Hill, making it one of the biggest, if not the biggest city in the country (by comparison New York City, the largest city in the U.S.A., has about 8 million people).
Harley: I wanna listen to the radio!
Batman: DON'T! (Harley press a button and a parachute coming out of the back of the Batmobile and Batman manages to stop)
Batman: Listen and listen good. You don't touch anything, say anything or do anything unless I tell you! GOT IT?!
Harley: (Scared) Yes, sir.
Harley Quinn (With a gun aimed at the Joker's head): Freeze, clown!
Harley Quinn: He's mine, Bats!
(The Joker nervously laughs at Harley, until he narrows his eyes and starts to get up)
Joker (To Harley): You wouldn't dare.
(Joker advances on Harley, the gun shaking in her hands)
Joker: You don't have the guts! Not in a million years would you-
(Harley, crying, shuts him up by shoving the gun closer to his face. She pulls the trigger, and out comes a rat-a-tat-tat sign. Batman and Robin sigh, while the Joker gives Harley a nasty look as she nervously smiles. He takes off his pilot's hat and smiles at Harley)
Joker: Baby! You're the greatest!
Harley: Oh, puddin!
(Harley jumps to the Joker's arms, as they both kiss)
Harley: Look, Bats. When I was a doctor I was always listening to other people's problems then I met Mister J who listened to me for a change and made everything fun.
Batman: You think it's funny when he hurts people?
Harley: It's just a joke.
Batman: Hope you're still laughing when it's your turn.
Harley Quinn (The Joker is ready to leave Gotham to the fait of the bomb he planted. But Harley wants to know...): Well what about all our friends? Ivy and Two-Face and... Hat-Guy and... Lizard Man and... Puppet Head...
Harley Quinn: (After arriving at the Jokers old hideout) How do you like our ha-hacienda?
Harley Quinn: Did you see the way I handled those creeps? Pow! Bam! Batgirl eat your heart out!
Joker: You really should loosen up dear, have a laugh now and then.
Joker: That bomb's going off even if I go with it! (laughs)
Harley Quinn: Laugh this off, puddin'!
Robin: What was she before she went bonkers?
Batman: A clinical psychiatrist.
Robin: (shrugs) Figures.
Batman: I need help.
Harley Quinn: Well, you've come to the right place! I recommend a lobotomy.
The song Harley sings, "Say We're Sweethearts Again" is from a 1944 movie Meet the People. Arleen Sorkin sang the song during her audition for the role of Harley and Paul Dini liked it so much that he wrote this episode to give Sorkin the chance to sing it as Harley.
This episode is episode 16 on the Batman: The Animated Series Volume 3 DVD.
The Joker's last line to Harley Quinn
"Baby, you're the greatest!" is in reference to Jackie Gleason's line as what his character Ralph Kramden says to Alice at the end of almost every episode of The Honeymooners.