Jesse and Yumyulack's relationship in general. While they do bicker and sometimes engage in dangerous Sibling Rivalry, Yumyulack makes it clear that only he can terrorize Jesse. Everyone else will either get shrunk, shot, or blackmailed. Jesse will also turn to him for advice if she's desperate.
Even before Season 2 and Word of Gay came along, Korvo and Terry have already acted like a cute couple. The two also bicker, but Terry has admitted he likes Korvo for being a smart stick-in-the-mud after a few weeks of him acting like a ditz.
Pupa is supposed to be evil, and a walking tyke bomb for the apocalypse. He also spends a portion of his subplots befriending animals or people.
Season 1
Pupa freeing a bunch of animals (dressed like fictional characters) from an auction.
When Korvo 'dies' during a magician act, the rest of the characters are genuinely heartbroken. They are also relieved when it turns out that he is still alive.
A minor one but in the same episode, instead of being upset at Korvo for faking his death, they begin holding each other's hands and running in a circle while shouting "Tricks! Tricks! Tricks!". For all their faults and squabbles, they genuinely love each other.
Terry and Korvo letting go of Funbucket.
In "The PATRICIA Device", it appears that Terry and Korvo have made a human friend, who is willing to show them around his man cave. In fact, the episode, in general, shows people being more accepting of the aliens.
Even though Molly's owner is annoyed at Yumyulack for shrinking him and locking him behind the wall, he considers it the best thing that ever happened to him, as it led to him meeting her.
Season 2
The season opener:
Korvo realizes that he can't give up the Pupa to the other Shlorpians on learning that Jesse and Terry need his help. He busts himself out of the cage they lock him into, and comes to resolve the conflict. Korvo gives Pupa another gun and orders him to defend himself, before grabbing Jesse's new dog and presenting it as the Pupa. He can be a Papa Wolf when the occasion calls for it.
It first is cruel of the "cool kids" to lie to Yumyulack and ordering him to have a sleepover so he won't find out about their real party. When they toss him into the trees, he comes back in a rage and prepares to murder them with a satellite. Before he can do it, a boy named Darryl shows up. He asks if the sleepover is still on as scheduled, and finds Yumyulack's human wall of adults cool. Yumyulack abandons the murderous intent and invites him to dinner.
In a black comedy sort of ways, Terry (whose snapped mentally due to Korvo changes in the timeline) finding peace and solace later on in his life.
The Solar Opposites show genuine guilt and remorse when they truly believe that they tortured Peter and they willingly accept their Fate Worse than Death punishment. Ironically this is one of the few times where they actually did nothing wrong and were framed.
Some of the ways the family tries to find fulfillment qualify. Terry delivers a baby on a bus and gives the dogs at an animal shelter a truckload of tennis balls. Yumyulack releases a chimp back into the wild and helps a ghost find rest by giving it's bones a proper burial in a cemetery.
Season 3
In the season finale the Solar Opposites finally come to realize that their negligence of the Pupa is the primary cause of his acting out. That the Pupa is more than just a key to their mission, but a genuine member of their family they have to care for and raise. They give up all of their science fiction devices and largely their whole identities in an attempt to truly get used to living on Earth and raising the Pupa and each other in a proper environment. And while the Solar Opposites are absolutely miserable, they are just glad that the Pupa is happy.
Season 4
In "The Ping Pong Table," Jesse and Yumyulack spend time apart due to being teased over their close relationship. Jesse tries to appeal to the Stacys by pranking Yumyulack at their school dance, but the Pupa forces her to flash back to when she and Yumyulack were first being grown. This reveals Jesse and Yumyulack both suffered from stunted growth, but once they were put together in the pot, they intertwined and flourished. Jesse and Yumyulack realize how much they need each other and put an end to their pranks, dancing together without a care.
"The Cardboard Dead Drop": After so much time being separated from her daughter, Cherie finally rescues Pezlie from the Bowinian church. Pezlie is elated to see her mother, crying out "Mama!" for possibly the first time. Cherie then swears to leave the Wall again to ensure Pezlie will never be harmed by the Wall again. Montez insists on going with her, despite Cherie's fears that he'll die just like everyone else who goes with her on these quests. He's not deterred.
"The Re-Visibility Bouillabaisse":
After a big fight, Terry apologizes and admits to Korvo that he wanted to meet Nancy Silverton to learn how to recreate a delicious pizza crust that Korvo had on vacation. He also admits he feels bad about not knowing as much as Korvo about how to help with sci-fi stuff like the ship, and genuinely admires Korvo's intelligence. Korvo admits he likes how much Terry needs him. Then they have invisible sex with a rolling pin as a dildo.
The season's Wall subplot ends with Sisto dead and Nova taking leadership in the wall, while Cherie, Montez, Pezlie, and a group of willing escapees set up a new life in the backyard. While it's unlikely to stay good for them, it's still a triumphant note, especially seeing Cherie finally have some mother-daughter time with Pezlie as she learns to walk. Not to mention the fact that this is the first time The Wall doesn't end its season on a cliffhanger after a shocking plot twist.
"The Unwanted Personification of Terry": Korvo tries to find where Terry left the ship and comes across a woman wearing his shirt. Korvo asks if she slept with Terry, and the woman says she wanted to, but Terry turned her down because "he said he was in love with some guy named Crumbo." Korvo initially gets super jealous, but it's clear Terry was talking about him. This shows subtle Character Development on Terry's part, since he previously slept around with anybody who offered, but now takes his relationship with Korvo more seriously.
Specials
In the Christmas special, Pupa goes to the church and sees someone crying there. After hearing from the guy that he caused his son to run away after being unable to accept his son being a bit bi. Pupa then looks for the son and convinces him to go back to his family. Thus reuniting the family and only asking for the father to unlock the Harry Potter whistle in return when joining them for dinner.
The climax of the Valentine's Day special has Terry and Korvo discover that they are capable of love, not just alien "affinity," and the intensity of their lovemaking is enough to restore love and save the world. The next year on Valentine's Day, they have a lovely wedding.
