In the movie, we have Patrick tagging along with SpongeBob on his quest to find Gary.
Patrick: Friends don't let friends go on dangerous quests alone!
Shows how loyal Patrick is to SpongeBob. Not to mention this is his second journey to travel outside Bikini Bottom with his best friend since the last time.
Film
Just the way Patrick is generally portrayed in this film. He’s nowhere near as idiotic as he is in the newer seasons and is genuinely shown to care about SpongeBob. He even starts searching around SpongeBob’s house after finding out that his snail is missing.
All the characters seem to be acting a lot nicer. Krabs is still a greedy boss, but one that generally cares for SpongeBob (and does not try to scam the audience either). And Squidward is a bit more tolerant of SpongeBob. He even goes to rescue him with the others (sure, he wanted to see Kelpy G, but still).
When the Krusty Krab closes down without SpongeBob to cook the Krabby Patties, Mr. Krabs is genuinely depressed to the point he concedes defeat by willingly giving the Krabby Patty Secret Formula to Plankton without incident, something that a shocked Plankton didn't expect. Krabs explains to Plankton of how much SpongeBob means to him, not just as a fry cook, but as a friend that is far more valuable than the formula itself.
SpongeBob and Patrick having a total blast in Atlantic City together, even when both of them lose all their money.
How Sandy discovers SpongeBob has gone. She comes over to his house, inviting him to join her on her rocket powered sled (she even refers to him as her “co-pilot”). Upon noticing he’s nowhere to be seen, she initially searches the whole house, and then bursts into the Krusty Krab, demanding to know where he is. Granted, she jumped to conclusions about Mr. Krabs keeping SpongeBob prisoner, but it’s a nice reminder how much she cares for the little square dude.
Sandy, Mr. Krabs, Patrick and Squidward each take turns telling King Poseidon how good a friend SpongeBob is.
When SpongeBob first met Sandy, he was amazed at how scientific she was. The squirrel doubted she could be a scientist, but the little yellow sponge encouraged her to pursue her dreams without any hesitation. She's been grateful for his total support ever since. They even share a hug that oozes with Ship Tease.
Sandy: He's the one that told me, no matter who I was or where I came from, I should follow my dreams. That's a friend, people! And that’s why in my eyes, SpongeBob is no criminal! He's the best little fella to ever walk the sea bottom, and that…that’s just how I feel about it. So please… don’t hurt him.
When SpongeBob first met Patrick, who was homesick and didn't had any friends, SpongeBob befriended him. The big guy even goes so far as to point out the only thing SpongeBob is guilty of is being the best friend he could ever have, having risked it all to save the snail he loves. He even formed a heart with his hands and placed them over his chest to show how much SpongeBob means to him.
When Squidward lost the Campy Award over SpongeBob and Patrick, the latter two lie to Squidward and tell him he won the award by a landslide. SpongeBob also gives Squidward his clarinet back, and tells him to never stop playing it. When we return to the present, Squidward says this to finish off his defense for the sponge. Rodger Bumpass’s delivery to the final line absolutely hits hard.
Squidward: Which is why, even though I can't stand SpongeBob, but at the same time...well, I love him. I love him...and I hate him! He's like, ice cream with salt on it! He's sweet, but super annoying. He's nice, and...NAILS-ON-A-CHALKBOARD annoying! Okay, fine, he's mostly super-freaking annoying! But...this little nattering noodge... is my friend. And he doesn't deserve to die.
Also during Squidward's performance in the flashback scene, SpongeBob and Patrick were the only people enjoying Squidward's playing.
Mr. Krabs' defense for SpongeBob. Like Squidward, Clancy Brown makes an excellent delivery.
Mr. Krabs: I'll be sayin' my piece now, if'in it be pleasin' the court. I suppose I could stand up here and tell you how SpongeBob changed me life. But, I won't. Might even speak about how he inspired me when I was just a small-time vendor with a broken down luncheonette. But, I won't. Heck, I'd probably mention how he encouraged me to start up me own restaurant, the Krusty Krab. [...] But, I won't. Nay, you'll hear no such praise from me. Because it wouldn't do him full justice. It wouldn't begin to describe the size of a lad's heart. Which...is huge. And he puts that heart into everything he does. Cooking, cleaning, serving up the delicious Krabby Patties. But that's the funny thing. I used to think me secret Krabby Patty formula was also the secret to me success. [...] It wasn't until SpongeBob came to work for me, that I realized the formula is more than just a list of ingredients, and flavor-capturing methods. It's more than a jealously-guarded recipe. The real secret formula...is sitting right here; SpongeBob SquarePants.
"The Secret To The Formula is You" is a musical number that was mostly used as a distraction so that the gang could rescue Gary, but the song itself is still very much heartwarming, as Patrick, Sandy, Mr. Krabs, and even Squidward and Plankton sing about how much of a good friend SpongeBob is.
Sandy can be heard joyfully shouting “SpongeBob!” during the chorus, and it’s adorable.
When King Poseidon realizes that he doesn't have any real friends, he breaks down crying. SpongeBob steps in and offers him his friendship, even after all the king had put him through. It's also a cute Call-Back to how SpongeBob befriended Patrick at camp.
The end of the movie includes a dedication to Stephen Hillenburg, the creator of the show, who sadly passed away in November 2018 from ALS. Better yet, it's accompanied by an early doodle of SpongeBob himself (known as SpongeBoy when this doodle was made) and the classic show theme song.
