For those of you out of the loop, Steven Universe is a Cartoon Network series created by Rebecca Sugar, who previously worked on Adventure Time. It chronicles the adventures of a young boy, Steven Universe, who is raised by three alien warriors, Garnet, Amethyst, and Pearl, after his mother, Rose Quartz, gave up her life to give birth to Steven. Rose led a rebellion against the tyrannical government of the Gem Homeworld in a colossal war that took place on Earth thousands of years ago, effectively saving the planet from total destruction. But that's just barely scratching the surface of this remarkable show.
Steven Universe is a surprisingly adult series, and it often deals with complicated themes such as post-traumatic stress disorder (PTSD), puberty, and same-sex relationships in a way that is both subversively educational for children and thought provoking for grown-ups. And sometimes there's also really awesome singing.
In the Season 4 episode, "Mindful Education," viewers learn that Connie instinctively threw a kid at school to the ground after bumping into him, and she's plagued with guilt. This leads to a massive amount of mental instability when she and Steven train as their fusion, Stevonnie. Because of the nature of fusion, both individuals need to be balanced emotionally and understand that they can't ignore their feelings.
Connie repressed how she felt and split the fusion mid-training session. Steven and Garnet both go to comfort her, resulting in the beautiful music sequence, "Here Comes a Thought," where emotions and traumatic memories are represented in the form of swarming butterflies, simulating the feeling of suffocation and flashbacks that often accompany PTSD.
The following day, we learn that Connie approached the classmate she beat up and made amends with him before she and Steven go off for another day of fusion training with Pearl and Garnet. Once again, Stevonnie experiences flashbacks, but this time, they're Steven's. Over the course of 107 episodes, Steven's seen a massive amount of combat for a 12-14 year old, and he constantly suffers from the guilt of having to fight and, unfortunately, hurt opposing gems.
The episode "Alone Together" is much like Stevonnie - "an experience." In arguably one of the best episodes of the series, Steven and Connie discover that they're able to fuse together, something that was once thought of as gem exclusive. At this point in the show, Steven and Connie are still pretty young, around 10-12 years old and when they fuse into Stevonnie, they're both thrust into the body of a young, developed woman (although Rebecca Sugar has gone on record, stating that Stevonnie is simply "an experience" and uses they/them pronouns, but that's a different list).
This is naturally pretty shocking. And also incredibly relatable - puberty for everyone is a massive shift in how the world perceives you, even though you're still the same person. Stevonnie goes through the episode being treated differently and is eventually objectified at a party by a pretty gross dude - something that every person watching will either experience in the future, or has lived with for years.
The idea of the nuclear family dates back to the late '40s and consists of the notion that the standard family unit consists of a husband and a wife with at the minimum, one child, in a "socially approved" relationship. Rebecca Sugar and company took this idea, crumpled it up, threw it in the garbage, and smashed it with Sardonyx's hammer. Due to the nature of Steven's birth, he was raised by the Crystal Gems for the majority of his formative years with his father, Greg, also present, but not with him every day.
This is incredibly similar to households kids are raised in today, be it by an aunt and uncle, godparents, or even by two parents of the same gender. The key factor in all of these scenarios is familial love and the idea that guardians will do whatever it takes to make sure their charges are healthy, happy, and know how much they're loved.
After suffering several defeats in battle and a massive loss in the shattering of Pink Diamond, the other three Diamonds of Homeworld ordered the retreat of all forces before firing a super weapon on Earth - a massive burst of light that corrupted many of the remaining gems on the planet, effectively warping and destroying the consciousness within the gems affected. This attack on the remaining gems pretty much amounts to genocide.
Throughout the series, we see the results of this attack in the form of corrupted gems which have turned into hostile beings, all due to this massive trauma caused by the Diamonds. The remaining gems feel survivor's guilt and PTSD.