The adorable theme song Steven strums out on his ukulele and how Garnet is the one who starts everyone clapping for him. Steven gets stars in his eyes when he's excited.
The theme song for the show (which is the song from the pilot, but in a higher tempo and keyed up). Steven's song holds so much meaning to the Gems that they'll sing it altogether. The song's optimistic message is arguably better expressed here.
Garnet calling Steven a buttface. It's not because she actually thinks he is a buttface as much as she knows that he'll be able to use a comeback to return before the fight with the knowledge to save the day.
In an overall sense, the sibling-like relationship between Steven and the rest of the Gems is so strong and genuine, that one would think they actually are related.
This is best exemplified by the fact that Steven has three distinctive relationships with the Gems. When he's with Amethyst, she's like a Cool Big Sis whom he's able to have fun and run around with, with Pearl she's a Parental Substitute who is constantly worried over his safety and well being, and with Garnet he's most eager to impress her because she has such complete faith in him and is able to call off Pearl and Amethyst when they're being a bit overbearing.
"You're one of us, Steven! We're not the Crystal Gems without you!" After Amethyst says this, Garnet smiles and nods.
At the end of the episode, the Gems assure Steven that he'll discover how exactly he summons his weapon. And Garnet remarks:
Garnet: Yes... in your own Steven-y way!
The reason why the Gems went out and stocked up on his favorite ice cream snack: because they knew it was Steven's favorite and heard it got discontinued. There's just something incredibly simplistic and sweet about the fact that they did that just because they wanted to do something nice for him for no reason other than just because.
Sadie letting Steven take the Cookie Cat freezer home.
"Laser Light Cannon"
Greg shedding a few tears at seeing Rose in the beam of the light cannon.
Rose using one of Greg's silly Catchphrases as the activation Code Phrase for the light cannon.
The Gems helping Steven hold the Light Cannon.
Greg may be a Bumbling Dad, and he knows that what the Gems do is way out of his league, but he still loves his son enough to help him out with whatever he might need, whenever he comes looking for him.
Similar to that, the relationship between Greg and Rose. Despite what the other Gems seem to think of Greg, Rose obviously loved him very, very much.
Amethyst and Steven hanging out at the beginning of the episode
"Let Me Drive My Van into Your Heart" is a song by one-man-band Greg Universe. When he performed it in concert, no one showed up... except Rose Quartz, the woman who would eventually give birth to Steven Universe.
Hell, the song itself is pretty heartwarming in its own right.
The motherly, almost neurotic concern Pearl shows for Steven. Once they show up at the Crystal Spire, she saves him from falling down a chasm and immediately wants to send him back to keep him safe.
Even though Steven did botch the mission, none of the Gems blame him. They even try to make him feel better about it afterwards, despite how much the tower obviously meant to them.
The entire premise of the episode, which is simply Steven trying to gather all the Gems in one place, just so they can all eat breakfast together.
Steven finds himself in Amethyst's "room", where she declares she's going to add him to the Junk Pile, but in a fun, sisterly, teasing manner, making it impossible to be anything but heartwarming.
Steven spends most of the episode trying to comfort and be a good friend to a fellow child named Peedee, who's having some serious daddy issues and is depressed by his new job. It just goes to show what a sweet, outgoing kid Steven is.
There's something really adorable about the way that Steven tries to help Peedee feel better, even though it's clear he doesn't understand why Peedee is sad. Even if he can't comprehend or fix the problem he can still try and support Peedee through it.
Peedee standing between his dad and Frybo in an attempt to defend the former, despite clearly being scared out of his mind.
"Dad, I'll... (beat) Are you gonna get another costume?" "(beat) Nah... I don't need another Frybo. I've got the Fry-man."
Steven and Greg bonding with a playful water fight.
After the Gems have returned and found that Steven has got his shapeshifting under control, Garnet tells the others that they should have more faith in Steven.
A YouTube comment summed up the climax as thus: Someone cares about you when they're concerned when you're in danger. Someone loves you when you've turned into a metamorphing cat monster and they still only see you as their son.
Steven unconsciously creating the bubble to protect them.
Especially when you realize that this was by accident, and he was risking his own life to save Connie.
Steven, the little Casanova, keeping Connie's bracelet safe for over a year. Until he worked up the nerve to talk to her and give it back. And what a way to give it back.
Connie: I'm going to disappear without making a single friend... (crying) Steven:(shows her the bracelet) ...We could be friends.
The fact that the scene looks symbolic of a man proposing to his lover using a ring (the bracelet).
Just the fact that they can even recall each other after an entire year.
Steven reassuring Connie when she's feeling overwhelmed.
When Amethyst and Pearl start to be too meddlesome with Steven and Connie, Garnet steps in to keep them from being a bother. Earlier on, she tells Steven to just talk to Connie, rather than let Pearl overplan it.
It's actually helped by making a Brick Joke into more of a Brick Heartwarming. When Steven asked them not to meddle, he said it would "Mess up his funky flow". Garnet repeats this as she drags Pearl and Amethyst away. While it's funny that she took a comment like that so seriously, it's also very heartwarming that she listened, took note and indeed took it completely seriously. Simply because Steven asked her to.
All the Ship Tease moments with Steven and Connie.
Though its because of this incident that Steven realizes the temple they're in revolves in the same manner as the teacup ride.
While all the Gems obviously love Steven, Garnet also shows him a lot of respect. Given Steven's insecurities about being a full member of the team, it's really very sweet.
Just how nice Garnet is to Steven. She's always really kind and supportive of him but it really comes out in this episode due to how much time they spend together. A particularly notable moment (A Crowning Moment of Kindness?) is when she carries him across a really intimidating-looking room full of traps rather than wake him from his nap, probably because she saw how tired he looked earlier.
To elaborate, from the previous two rooms, and due to the spinning nature of the pyramid giving him nausea, Steven gets highly nervous upon seeing the third trap and ends up fainting. But when he comes to and finds that Garnet had carried him through the chamber, she just tells him that he was taking a nap and remains encouraging, rather than telling him that he fainted or collapsed.
Note also that when Pearl goes into exposition-mode about how the place worked to begin with, Garnet immediately tells her "Steven already figured that out". Garnet clearly listens to what Steve says and always takes him seriously, which Pearl in this case, probably with her tendency to think a bit highly of herself, apparently forgot. She's visibly embarassed to be called out on it, too.
Steven's speech about Purple Puma's backstory, which is pretty heartwarming in itself:
Stephen: Can't we have this? Can't we just... wrestle?
After realizing how much bottled-up anger Amethyst holds in towards their no-nonsense expectations of her, Garnet and Pearl especially decide to go along with her wrestling facade and pretend to be the Heels, allowing themselves to be "beaten" so that Amethyst and Steven can have a good time.
The "fight" between Pearl and Steven has her pretending to be knocked out by him in an overly-dramatic fashion that's very reminiscent of a parent or older-sibling having a mock fight with a young child.
Amethyst regretfully apologizes to Garnet while she's pretending to be knocked out, who apologizes in return.
Lars's restored love for Tiger Millionaire by the end of the episode after Steven knocked a drink out of his hand by being too "in character".
Lars: I love you, Tiger Millionaire
Steven's complete and utter adoration of the lion, and the lion being completely gentle and passive to Steven in response, not to mention the lion eventually rescuing Steven and helping him reach the desert glass.
Just the image of Steven and Amethyst taking a nap under a pillow fort they made. Further cementing their sibling-like relationship without even saying anything.
Garnet gently teasing and reassuring Steven that nothing can harm him in the desert at the beginning of the episode. Very cute.
On two separate occasions, Steven grabs one of the Gems by the hand as he leads them to a video game he thinks they'll enjoy. He does this to Pearl and Garnet respectively, and it is adorable.
At the beginning of the episode when Steven is in danger, all three gems work together to save him. Garnet catches him from his fall and prevent him from being hit by a monster's projectiles, then Amethyst carries him to safety while Pearl covers their escape.
Steven, wondering if Opal still retains Pearl and Amethyst's memories, is reassured that it's still them by Opal gently singing "Giant Woman" to him.
Steven, upon learning that Gems don't really celebrate birthdays, vows to throw a party for each Gem, hoping to make all of them as happy as his own birthdays have in the past.
A small one, but upon finding a aged Steven laying in the sand, Lion immediately grabs him and rushes him to the other Gems, showing that even Lion is concerned for his new friend's safety.
And after he transports Steven to the Gems, he lets Steven sit/lie against him.
Sadie attempts to cheer up the greatly aged Steven after he has a breakdown in the donut shop, despite not even recognizing him at the time.
The moment when Steven finally reverts to his normal age and the Gems tackle him out of absolute joy should definitely garner a huge sigh of relief.
Garnet keeps wearing the cape and crown she had on for the party Steven tried to throw for her throughout the episode. When told she doesn't have to wear it anymore, she says that "it makes [her] feel important". Dawe.
Steven pretends to fall to perform the classic pie in face gag. Pearl, not realizing the joke and being... well, Pearl, takes about half a second to stand up and catch him, preventing him from falling on his face.
When Pearl, trying to save Steven, fails at the pie gag because she's so upset, Amethyst says "Are you trying to kill him faster?!?" Normally Pearl might scold her for saying something so insensitive, but she's so distraught that instead she cries harder and throws her arms around Amethyst for comfort.
"Lars and the Cool Kids"
Throughout the entire episode, Steven goes out of his way to help Lars pique the interest of the alleged "cool kids", all while just being his own sincere, goofy, loveable self.
The end of the episode, in which the true nature of the moss is revealed and the kids gaze dumbstruck at the sight of the flowers floating over the city.
When it's all over, Lars tries to give Steven some very well-deserved credit for saving the day. Steven immediately interrupts him to say Lars was the one that drove them all up there. That's pretty big of both of them.
And at the end, Steven and Lars look at each other, smile, and give each other a "chest-five," nodding back to when Steven did it to Lars earlier in the episode.
Steven giving Onion his Ranger Guy even though he tried to destroy the town because Steven realizes he needs it more.
The conversation between Steven and his dad at the end of the episode.
Greg: You went through all that trouble for a toy? Steven: It was more for the memories than the toy.
Pearl offhandedly mentions that she'd be happy to show Steven real sword fighting techniques. Then she feels Steven's hand on her head and looks up to see him staring at her excitedly with stars in his eyes.
The Gems don't blame Steven for what happens to Pearl getting stabbed by her own hologram because they know she is going to be fine.
Amethyst comforts Steven by telling her that what happened to Pearl usually happens to her. Garnet teasingly reminds her that it always happens to her. Steven laughs and cheers up.
And there's Steven's reaction when Pearl is finally regenerated. He runs straight over and hugs her, with Pearl just giving a chipper little "Miss me much?". Aaawe.
The way she's shocked for a moment as he almost bowls her over before smiling gently at him and placing a hand on his hair.
Steven tends to Pearl's Gem the entire two weeks she's gone. He talks to it, keeps it warm, and brings it with him to watch a movie. Clearly, he's doing his best to look after her the same way she looks after him.
"Lion 2: The Movie"
Just about every second Steven and Connie spend together in this episode can induce diabetes. Despite having very different lives from each other, they very much enjoy having fun together.
Steven and Connie can be seen holding hands while they ask for movie tickets.
In the short amount of time that they appear, the Gems make an effort to appear impressive to Connie for Steven's sake, in a rather parent-like fashion.
Steven's adamant determination to show the Pizza family that the Crystal Gems aren't just destructive assholes. He wont stand for anyone thinking lowly of his friends/family.
While this is mostly a pretty scary episode, there are lots of little heartwarming moments. Steven eating four cans of Cream Corn just so the four of them can go play minigolf is very sweet, and the Gems actually really do look sorry when they say they can't go. It's cemented further when they come back from their mission and are all happily showing him the stone they brought, clearly thinking he'll find it exciting. Too bad they interrupted him at a bad time this once... and of course, at the very end, they still end up playing minigolf. Aaawe.
Garnet: Guess what? We have time to hang out now.
At the end, Steven apologizes for getting mad at the Gems, understanding that they sometimes just couldn't spend time with him when he wants it. They apologize in turn for having to always leave him behind.
Pearl takes Amethyst biting her on the arm without complaining, because she was too concerned about Steven to care about Amethyst bothering her at the moment. Likewise, Amethyst doesn't retaliate when Pearl accidentally elbows her in the face.
At the end, Garnet does end up wearing the golf pants Steven showed her, probably just because he wanted her to.
Rebecca Sugar in interviews talking about how her brother Steven (who's the basis for the titular character) being there for her while working on the show and before that. If you think about how the other three gems are all parts of her, this seems even more heartwarming when watching the show.