- "It's not my BIRTHDAAAAAAAAAAYY!!!!!"
- ―Squidward delivering the most famous line of the episode
"Opposite Day" is the second segment of the ninth episode of SpongeBob SquarePants.
Squidward is still asleep, only to be woken up and annoyed by SpongeBob and Patrick, who came into his house to throw a surprise birthday party for him, despite that it isn't really his birthday. After they leave, he calls Patty Rechid from Bikini Bottom Realty to arrange for his house to be sold, so that he may move out of Bikini Bottom. He is warned that, if his home is surrounded by bad neighbors, the house may not be sold. Squidward is convinced that SpongeBob and Patrick may ruin his chances of selling his house. Squidward tells SpongeBob that it is "Opposite Day", and that everyone must act opposite to how they usually act. SpongeBob believes him, and informs Patrick, who forces himself to stop exhaling, until SpongeBob exclaims, "not that opposite!" A montage of the two doing "opposite" things, such as talking backwards and acting as Gary's pets, is then shown. Squidward's plot soon begins to backfire on him. SpongeBob "fixes" (damages) his house, and a shocked Squidward cleans the debris with a bulldozer. SpongeBob concludes that Squidward is acting like him, and he must therefore act like Squidward. While Squidward is still fixing SpongeBob' house, Patty arrives, and SpongeBob and Patrick both pretend to be Squidward, giving her a tour of the house, while describing it negatively and doing the opposite of what she asks. When Squidward realizes what is going on, he rushes to his house and attempts to explain the situation to Patty, who, upon hearing that he is "Squidward" as well, finally sees through his game and accuses them of intentionally messing with her and leaves. Squidward begged Patty to sell his house, but she refuses. A furious Squidward shows SpongeBob and Patrick how much he "hates" (Squidward was not being sarcastic, although SpongeBob and Patrick were) them by attempting to run them over with a bulldozer, scaring SpongeBob and Patrick out of their wits as he is now on the warpath against them with SpongeBob saying "Patrick, Do you ever feel that Squidward likes us too much?".
- After Patty leaves, Squidward lays on the ground in shame. In the close up of his face, SpongeBob has his belt around his waist, but it was wrapped around his head.
- When Patty says, "Are there any more Squidwards I should know about?", the captions simply say, "Are there any more Squidwards?".
- When SpongeBob puts the belt around his head, the belt buckle and the piece of belt that goes through it disappears.
- Patty Rechid was voiced by Lori Alan, who also does the voice of Pearl in the series but, the end credits mistake her to be voiced by Sirena Irwin.
- When SpongeBob offers the realtor to see the rest of the house, the captions just say, "Would you like to see the rest?"
- When SpongeBob and Patrick are talking backwards they are saying: "Hey, Patrick", "I give up", and "To get to the opposite side". The captions says "(speaking gibberish)". When it reran on October 20, 2011, it sounded like they're speaking Russian.
- On the Drawn Together episode "Terms of Endearment", Wooldoor Sockbat has a similar joke based on this episode.
- Squidward would drive a bulldozer again in "Big Sister Sam" and "New Fish in Town".
- Opposite: Patrick and SpongeBob turn opposite colors, they speak backwards, they eat and live like Gary, Gary eats with fine dining, when SpongeBob and Patrick blow a bubble, they get blown up into bubbles themselves.
- In one scene, Squidward's house ear has window, then it's gone.