The "Be more Tea" Lipton commercial; Kermit, in a New York City full of Animals (Yes, really. hundreds of that angry, beastly Muppet), decides to "Be more tea" and spends the commercial doing good deeds, like helping an old man Animal cross the street and cheering up a Baby Animal. At the end he has this exchange with Miss Piggy;
Piggy: Kermit, how do you cope with all these Animals!?
Kermit: Just be more tea!
Mary and her students bidding each other farewell before she and Gary embark to Los Angeles.
Mary: Oh, there's the bell. That means it's time for Spring Break.
Mary: Don't worry. We'll be back to studying in two weeks.
Kermit's reunion with Fozzie.
Kermit: Hi-ho, Fozzie.
Fozzie: [without missing a beat] Hi-ho, Kermit. (beat) Kermit?!
Not just that, Kermit kisses Miss Piggy on her snout. Say it with me everyone, "Awww...."
Kermit: ...will you stay? ...for me?
Along the same scene, Floyd giving Animal his old drumsticks back, saying that he'd been saving them for years and telling him "You know what to do." It's a very sweet nod to the two's long friendship.
Loved how the first version that Kermit sang became so memorable and uplifting? Try hearing a whole chorus of it! Definitely helped the in-universe audience go "ALL MY MONEY" and boosted the donations!
There are reports of entire theaters singing along with it.
Animal looks truly happy for the first time in the movie, finally back to playing the drums again!
"Pictures in My Head," in which Kermit recounts how even though the other Muppets' acts would drive him crazy, he couldn't live without them.
The moment when Kermit takes out his half of the photo of himself and Piggy. And from behind him, hears her softly say, "You saved it...". When he turns around, she is holding up her half and they put the two pieces together. Sweeeeeeet.
The speech Kermit gives to the Muppets after the telethon ends.
Kermit: It doesn't matter if nobody believes in us. Because I believe. I believe in you... and you... and you, and - all of you.
Then afterwards when they walk outside and find a massiveFan Mob waiting for them, cheering loudly and holding up signs... *sniff*
"Maybe you don't need the whole world to love you. Maybe you just need one person..."
Even more as it's a Call Back to the song played at Jim Henson's funeral.
Because, in fact, it was Jim's favorite song. Awww...
In a crazy sort of way, the revelation that Gonzo had been secretly dreaming of a reunion, and had worn his stage outfit under his suit for years.
The entire movie is this trope; reviving a dying franchise to its former glory for a brand-new generation while keeping to its old, much-cherished tone.
What's particularly showing is the number of big name celebrities that make guest appearances to show their support for the franchise...most with one or two minute appearances.
According to the production team, more celebs volunteered for cameos than they could fit in the script.
Veronica's defrosting over the course of the telethon, until she's openly cheering for the Muppets after their performance of "The Rainbow Connection."
The various Shout Outs to Jim Henson, especially seeing the photo of him posing with Kermit right in the middle of all the other celebrity photos on Kermit's wall.
The Muppets did various cross promotions for this movie, including (at one point) appearing on Professional Wrestling shows. The people doing the most fan-squeeing? The wrestlers.
When you consider wrestling as all around dudes in speedos and grappling (this troper having been a wrestling fan), seeing this is just amazing. This goes to show that all sorts of people love the Muppets and they aren't afraid to show that.
The way Kermit, after thanking Walter for helping him get the gang back together again, tells him "welcome aboard" — no fanfare, no big speech. Walter is shocked; it's been a life-long dream of his to be accepted among the Muppets, and to Kermit it almost goes without saying that of course he's welcome to the team.
In a more Meta example, the fact that there hasn't been a ton of nostalgic uproar about the film is quite heartwarming in and of itself.
While it gets outdone later and she's very spiteful about it, Miss Piggy returning to do the show for the rest of gang despite her current relationship problems with Kermit is both very sweet and highly professional of her.