Goof: When Ralph and Lisa go to Krusty's show, Ralph spills chocolate ice-cream on Lisa's dress, however when Lisa tells Ralph that she doesn't love him, the stain is gone.
In this episode, we learn that Ralph is Chief Wiggum's son.
The "Krusty Home Pregnancy Test" contains the warning "May cause birth defects."
Goof: Willy mentions that he "did not even cry when my own father was hung". In season 10's "Monty Can't Buy Love", we meet Willy's parents both alive and well in Scotland.
Lisa: Ralph thinks I like him but I only gave him a valentine because I felt sorry for him.
Homer: Ah, sweet pity. Where would my love life have been without it?
(Watching The Krusty Show)
Bart: I'd give anything to go to that show!
Homer: I'd sell my first-born son!
Homer: You'll do as you're told!
Ned: If you think I'm cuddly and you want my company, come on wifey let me know!
Homer: Six simple words, I'm not gay, but I'll learn.
Groundskeeper Willie: I didn't cry when me own father was hung for stealing a pig, but I'll cry now.
Principal Skinner: Good evening, everyone, and welcome to a wonderful evening of theater and picking up after yourselves.
Homer: You know, one day honest citizens are going to stand up to you crooked cops.
Chief Wiggum: They are!? Oh no! Ha-have they set a date?
Bart: Oh it isn't fair. I'm ten times the Krusty fan you are. I even have the Krusty home pregnancy test!
Ralph: The doctor said I wouldnt have so many nosebleeds if I kept my finger outta there.
Ralph: Uh... so... do you like..... stuff?
Guy: Where do you want these beef hearts?
Lunchlady Doris: On the floor.
Guy: It doesnt look very clean.
Lunchlady Doris: Just do your job, heart boy.
Miss Hoover: You may now exchange Valentines.
Ralph: Miss Hoover, I glued my head to my shoulder.
Ralph: My parents won't let me use scissors.
Miss Hoover: The children have a right to laugh at you, Ralph. These things couldn't cut butter. Now, take out your red crayons.
Ralph: Miss Hoover. I don't have a red crayon.
Miss Hoover: Why not?
Ralph: I ate it.
Moe: (Reads his valentine) "To Moe. From your secret admirer."
Barney: Yoo Hooooo!
Moe: Oh God, no!
(Barney blows a kiss and belches)
Grampa: Bah, this is just another Hallmark holiday cooked up to sell cards.
Jasper: Aww... a Valentine from my daughter!
Abe: Can I have the envelope?
Bart: Cool, I broke his brain.
Homer: I've heard 'em all. I like you as a friend... I think we should see other people... I no speak English...
Lisa: I get the idea.
Homer: I'm married to the sea... I don't want to kill you, but I will.
Ralph: I Choo-Choo-Choose you.
Mediocre Presidents Song
Kids: We are the mediocre presidents.
You won't find our faces on dollars or on cents!
There's Taylor, there's Tyler, there's Fillmore and there's Hayes.
There's William Henry Harrison,
Harrison: I died in thirty days!
Kids: We... are... the... adequate, forgettable, occasionally regrettable, caretaker presidents of the U-S-A!
Bart: I'll go, disguised as you.
Lisa: What if he wants to hold hands?
Bart: I'm prepared to make that sacrifice.
Lisa: What if he wants a kiss?
Bart: I'm prepared to make that sacrifice.
Lisa: What if he…
Bart: You don't want to know how far I'll go.
Blackboard Joke: I will not squeak chalk (followed by squeaking noises).
Couch Gag: An alien is on the couch. When he sees the family coming in, he pulls a lever, opening a trap door and hops in. The family sit down as if nothing happened.
The song Ned sings to Maude is a parody of "Do Ya Think I'm Sexy?" by Rod Stewart. Ned has cleaned up the lyrics a little.
American poet Robert Frost appears on Krusty's show reading his poem "Stopping By Woods On A Snowy Evening." He is less than amused when Krusty dumps snow on him.
Song: Monster Mash
The song during closing credits is "The Monster Mash" by Bobby "Boris" Pickett. The disc jockey on KBBL also plays the song at the beginning of the show in honor of Valentine's Day. He tries to explain what's romantic about it, but the other DJ just says, "You played the wrong song, didn't you?"
The scene of Principal Skinner's memory of Vietnam is reminiscent of the movie Apocalypse Now. The characters on the boat all resemble characters from that movie. Also, there is a picture of a soldier where Skinner was sitting. This was the picture of the person they were trying to find in the movie.
Krusty: You try to run, try to hide, break on through to the other side!
Aided by a psychedelic background and flower child clothes, Krusty sings a rendition of The Doors' song "Break On Through".
Homer: You know, one day, honest citizens are gonna stand up to you crooked cops!
A quick and funny reference to the 1973 movie Walking Tall..
Krusty: Why do they call this the Pee Monkey?
At one point on The Tonight Show Starring Johnny Carson there was some manner of small mammal brought from the San Diego Zoo. It then proceeded to be put on him and then it urinated on his head.
Bart: Hasta la vista, Abey!
While Bart was trying to do an impression of The Terminator, he and Milhouse slightly recreate the assassination of President Abraham Lincoln.
I Love Lucy
The title of this episode is a reference to the 1951-1957 CBS series I Love Lucy.