When Candace can't find a birthday present for Jeremy, Phineas and Ferb help her create a Scrapbook-aganza of all the memories they spent. Meanwhile, Doofenshmirtz invents a Worst-Fear-inator that makes people's worst fears come true.
Tropes:
- Actor Allusion: Major Monogram says that tonight is "Horrific Movie Night", which was in reference to writer John Mathot's former blog "Horrible Movie Night".
- Anything but That!: When the vending machines tie up Doofenshmirtz and start Force Feeding him with the food inside them, he screams, "No, not that! Anything but the fake red licorice!"
- Bait-and-Switch Comment: After Candace goes through the test run for the giant scrapbook, Candace says "I have a few notes here... It's perfect!!!"
- Birthday Episode: For Jeremy.
- Call-Back: Dr. Doofenshmirtz's fear of vending machines taking over the world comes from Phineas and Ferb The Movie: Across the 2nd Dimension.
- Continuity Nod:
- When Buford says a flower smells like his grandmother, Phineas says he thought his grandmother smelled like ant pheromones, but Buford says that was his other grandmother.
- The giant 3D scrap-book references several moments from previous episodes, like the ride through the car wash in "At the Car Wash", the sandal commercial Jeremy did in "Let's Take a Quiz!", and the wheelbarrow race at the Johnson Family Reunion in "Run, Candace, Run".
- Cute Mute: Isabella for a majority of the episode. She doesn't speak until the last scene where she had been working to earn her "24 Hours of Silence" patch.
- Double-Meaning Title: The "Cheers" part refers to Jeremy's birthday surprise while "Fears" deals with the Worst Fear-inator. The name is also a Shout-Out to the band Tears for Fears.
- Gainax Ending: The ending reveals Isabella won a patch of spending a whole day silent and got to understand Ferb's life. We then zoom in on Ferb's mind, which has loads of inner dialogue.
- Hurricane of Puns: When Doof finds out that Perry isn't afraid of anything, he makes light of him being trapped. For context, Perry is hanging upside-down from a rope.Doofenshmirtz: I guess you'll just hafta... hang around! Ha ha ha! Oh, wait, this one's better: I'll just leave you here because you're all tied up! Ha ha ha! W-W-Wait, one last one, you're gonna love it: See ya later because it isn't my tail that's upside down! (Beat) No? No, no, I shoulda stuck with the first two, you're right.
- I Know What You Fear: The Worst Fear-inator makes the worst fear of whoever it zaps come to life; Doofenshmirtz's worst fear is vending machines taking over, the machines' is a gigantic rolling quarter, and Candace's is the Big Idea flying away before Jeremy can see it. Since Perry has no worst fears to begin with, he is not affected.
- The Immune: Perry is fearless, thus the Worst-Fear-inator has no effect on him.
- Intelligible Unintelligible: Buford is able to understand Candace's sullen mumbling fluently, though he misinterprets her problem at first.'Candace: Thnk yu...
Buford: Oh! Oh! She just said, "Where's Perry"!
Candace: You have got to work on your sullen! - No-Sell: The Worst-Fear-inator has no effect on Perry.
- Retcon: Perry is unaffected by the inator because he's "fearless", but earlier in the series, he was clearly afraid of being sent away if his cover is blown, as seen in "Phineas and Ferb Get Busted!".
- Save the Villain: When Doofenshmirtz accidentally shoots himself with the Worst-Fear-inator and manifests an army of vending machines bent on taking over the world, the vending machines start attacking Doofenshmirtz. Perry, sensing Doof's terror, goes back inside the lab and shoots the vending machines with the Inator, causing their worst fears to appear (a giant killer nickel). Doofenshmirtz then thanks Perry the Platypus, willingly destroying the Inator and even offering to validate Perry's parking fee.
- Shout-Out: When Doof is hit by his own inator, he thinks he will be safe as long as he doesn't think about his fears. But after a rumbling, he says, "I couldn't help it, it just popped in there!" This is pretty much word for word what happens with Ray Stantz in Ghostbusters (1984).
- Strangely Specific Horoscope: Technically, fortune cookie, but a man at a restaurant gets a fortune that reads, "You will share your cocoa with a long-necked teenager". His date's fortune cookie reads, "Your boyfriend's gonna get a fortune cookie at a French cafe.
- Tempting Fate: As Candace gets shot accidentally by the Worst-Fear-inator, she says that she's glad that her mother is gone because she's afraid that the scrapbook will fly away before Jeremy arrives. Guess what happens to the scrapbook...
