- Squidward Tentacles
- SpongeBob SquarePants
- Incidental 64
- Incidental 36
- Incidental 25
- Incidental 49
- Sandy Cheeks
- Patrick Star
- Incidental 48
- Incidental 42
- Incidental 10
- Incidental 40
- Incidental 45 (light blue)
- Incidental 6
- Incidental 27
- Incidental 39
- Incidental 41
- Incidental 46
- Incidental 90
- Incidental 49
- Incidental 151
- Gramma (debut)
- Scallops and clams
- Eugene H. Krabs
- French narrator
- Squidward's house
- Dr. Actor
One morning in Bikini Bottom, SpongeBob tells Squidward it's time for work and says "another day, another dollar," but Squidward says, "more like another nickel," which makes SpongeBob laugh uncontrollably. Squidward then goes through a whole day at work with SpongeBob laughing, and even at night. The next day at work, after SpongeBob told the "nickel joke" to the customers, Squidward has decided he has had enough of SpongeBob's incessant laughter. He then sees SpongeBob hurting himself when he laughs, so he tricks him into believing that SpongeBob has a laugh-related illness. According to the made-up disease, if SpongeBob laughs one more time in the next 24 hours, his laugh box will explode, and he will never be able to laugh or giggle again.
For the rest of the day, SpongeBob fights every single urge to chuckle. First, he sees Patrick trip over a banana peel several times and runs away. Next, he sees that whoopee cushions are all over the town. Last, he sees a pie truck in an accident and some of the pie land on some fish. In a drastic measure, he buries himself never to be interrupted by a joke during the night. The next morning, SpongeBob discovers that he has completely lost the ability to laugh. He tells Patrick that he has lost his laugh, but when Patrick looks inside SpongeBob and lights a match, he runs around in circles.
Later, SpongeBob goes to the Krusty Krab to tell Mr. Krabs that he has lost his laugh. Mr. Krabs says that money always makes him laugh, but SpongeBob doesn't feel a tickle. Next, SpongeBob consults Sandy. Sandy gives SpongeBob books about laughter. SpongeBob reads the books, but still doesn't have any effect on his laugh box. Now utterly grief-stricken, all SpongeBob can do is bawl his eyes out, meaning more noise than ever. Feeling guilty, but still wanting peace and quiet, Squidward finally confesses to the sad SpongeBob, as his weeping has been more annoying than his giggles, and after Squidward admits everything, SpongeBob laughs to see it has been a good joke and Squidward joins in the laughter. When Squidward says, "You even fell for the thermometer in the boiling oil routine!" SpongeBob immediately stops laughing, saying it's not really funny and goes inside his house. When Squidward laughs too much, his laugh box goes out and is taken to the hospital.
Later, it is revealed that Squidward has broken his laugh box and Purple Doctorfish points out that one of the others has given him half of their laugh box. It isn't Patrick, Mr. Krabs, or Sandy; it was SpongeBob, who shows the bandage to prove it. Shocked, Squidward starts to laugh like SpongeBob, to his great horror. He and SpongeBob laugh together before Squidward runs out of the building still laughing like SpongeBob in maniac state. SpongeBob then says, "Ah, there he goes off to share his laugh with the world," followed by his own laughter.
|( ‣ ) Associated production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
• Happy Sponge Chase Vibes - Nicolas Carr [Title card]
• 12th Street Rag - Sage Guyton, Jeremy Wakefield [opening]
‣ The Tip Top Polka/The Cliff Polka - Chelmsford Folk Band [at the Krusty Krab]
• Sponge Monger - Sage Guyton, Jeremy Wakefield [Squidward annoyed by SpongeBob's laughter]
• Sea Weed Seal - Steve Belfer [the next day]
‣ King Conga - Dennis Farnon [SpongeBob's sides aching as he laughs]
‣ Comic Walk - Sidney Torch [Squidward warns SpongeBob about breaking his laughbox]
‣ Like Strange - Kenny Graham ["Listen, SpongeBob, this is serious."]
‣ Dancing the Hula - Kapono Beamer ["Hey, Patrick, you wanna hear a joke?"]
‣ Funeral March (b) - Richard Myhill [iron laugh box]
‣ Comic Walk - Sidney Torch [Squidward tells SpongeBob to stop laughing]
‣ Flop and Go A - John Fox [whoopee cushions]
‣ Try On and On A - Hans Ehrlinger [pie truck]
• Grass Skirt Chase - Sage Guyton, Jeremy Wakefield [SpongeBob runs away]
• Vibe Sting - Nicolas Carr [SpongeBob tries to laugh but can't]
‣ Drama Link (g) - Hubert Clifford ["I've lost my laugh!"]
‣ Drama Link (d) - Hubert Clifford [SpongeBob screams]
• Steel Licks 3 - Jeremy Wakefield ["It's terrible, Patrick. I can't laugh anymore."]
‣ Hawaiian Cocktail - Richard Myhill [SpongeBob enters Krabs' office]
‣ Botany Bay (c) - Robert Alexander White ["You've come to the right place, son."]
‣ Dancing the Hula - Kapono Beamer [at Sandy's]
‣ Pua Paoakalani B - Kapono Beamer, Queen Lili'uokalani [SpongeBob depressed]
• Mary Had a Little Lamb - Brad Carow [Squidward playing clarinet]
‣ Kamakani B - Kapono Beamer [SpongeBob crying]
• What's This - Nicolas Carr ["This charade has to end!"]
‣ Comic Tension (a) - Dick Stephen Walter [Squidward goes up to SpongeBob's door]
• Steel Licks 1 - Jeremy Wakefield [Squidward admits he made it up]
• Sad Joke - Nicolas Carr ["You mean my laugh box isn't broken?"]
‣ Hawaiian Link (b) - Richard Myhill ["I could laugh the whole time?"]
• 12th Street Rag - Sage Guyton, Jeremy Wakefield [SpongeBob, Squidward laughing]
‣ Bashful Eyes - Kapono Beamer [Squidward in the hospital]
• Seaweed - Steve Belfer [ending]
- This episode is available on the Lost in Time DVD and VHS, Season 4 Volume 1, Bob Esponja Vol. 1, First 100 Episodes, Double Feature Volume 2, The Best Day Ever, 2-Season TV Pack, The Ultimate SpongeBob Box Set, SpongeBob SquarePants Vol. 5, Complete Fourth Season, From the Beginning, Pt.2, The SpongeBob SquarePants Collection, The SpongeBob SquarePants 8 Season DVD Collection, Favorite Episodes Volume 2 The Third & Fourth Seasons, and The Best 200 Episodes Ever DVDs.
- This episode was originally going to be named "Unfunny Pants," but was later changed to "Laughbox" when Nick announced the episode.
- The title card background for this episode is similar to that of "Squirrel Jokes."
- SpongeBob reuses the line "Another day, another dollar" from the episode "Krabby Land."
- A shot of SpongeBob laughing in this episode was used in an advertisement for SpongeBob DVDs in 2009. 
- Mr. Krabs is absent when the Krusty Krab closes at the beginning.
- It should be noted that when Squidward reads the thermometer temperature from the boiling oil as 175 degrees, this is likely Celsius, which is the metric system. This is because 175 degrees Celsius, which is 347 Fahrenheit, has to be the minimum temperature for cooking oil to not boil, but still be very hot.
- The laughing machine SpongeBob is attached to is similar in appearance to an "iron lung" breathing aid.
- The fez hat Squidward is wearing when he says SpongeBob became a sad sack was previously seen in "Good Neighbors."
- When Squidward plays his clarinet after the "Later that same evening" time card, he plays the tune "Mary Had a Little Lamb" as he did in "The Paper," and he still plays it incorrectly.
- This was the first episode to be written by Luke Brookshier, Tom King, and Steven Banks.
- This episode premiered separately from its sister episode. This previously happened with "Hooky"/"Mermaid Man and Barnacle Boy II" and "Shanghaied"/"Gary Takes a Bath."
- This episode marks the second time Squidward's house has grown hands, after "Good Neighbors."
- This was Todd White's final episode as character designer before he was replaced by Robertryan Cory.
- This is currently the only episode where both "12th Street Rag Revisited" and "12th Street Rag 3" play.
- In the Croatian dub, the episode's title is "Smjehuljak" or "Laughter."
- On the April 1, 2017 airing of this episode, the episode's theme song is replaced with an April Fools/Rock version.
- While SpongeBob is laughing on his way to work, parts of his belt flicker between black and white.
- When Sandy tells Patrick if he wants to hear a joke, her tail is there. When SpongeBob says, "Sure. I'd love a good laugh" and it cuts right back to them, Sandy's tail is missing. Then, in the next shot, it is back again.
- When Sandy says, "What has four wheels and flies?" when telling Patrick her joke, her voice is out of sync with the animation.
- When SpongeBob says, "Get a grip on yourself, SpongeBob. You're in control," his red tie turns brown for a split second. Also, in the same scene, part of his white collar turns red for a split second.
- When Patrick is about to go inside SpongeBob, his pants are a darker shade of green for a second. Also, in the same scene, one side of SpongeBob's belt is white instead of black for a split second.
- When Sandy pulls down a chart of the body, her tail disappears for a split second.
- When Sandy explains the science of laughter, she pulls down a diagram of a fish. However, the diagram shows the fish with lungs even though fish have gills.
- When Squidward wakes up from a coma, Sandy’s zipper and badge is missing.
- When SpongeBob shows the scar to reveal his transplanted laugh box, his pants are much higher than usual.
- When Squidward bursts through the hospital wall near the end of the episode, the heart monitor is still running.
- When Squidward runs off his bed in the hospital, it seems like he is walking on air.