WARNING: The following contains spoilers for Steven Universe Future episodes "Little Graduation" and "Prickly Pair," which aired Dec. 28 on Cartoon Network.
While most of the residents of Beach City and Little Homeworld have been making their way in the world on Steven Universe Future, there's been one notable exception. Steven himself has become more isolated from his friends while they learn more about themselves. All of that is weighing on him in a way nothing has in the past, breaking Steven's hope in a way we haven't seen before. The midseason finale pushes Steven into a more depressive state than he's ever been before.
SADIE KILLER & THE SUSPECTS
After spending the beginning of the series in a rut, Sadie Miller embraced her musical side and started playing songs with Jenny Pizza, Sour Cream and Buck Dewey. Together they, Steven, came up with the band Sadie Killer and the Suspects. The group was going on tour at the beginning of Steven Universe Future, suggesting a bright future. However, the tour was followed by an amicable break-up, to Steven's shock, in "Little Graduation."
Jenny and Dewey are revealed to be leaving music. Jenny has developed an online business, selling novelty sweaters for cellphones. Meanwhile, the taciturn Dewey has surprised everyone by being accepted into a medical program in college. Jenny points out this will eventually end with Doctor Dewey, which is a surprising (but somewhat fitting) role. Sour Cream and Sadie still appear to be focusing on music, however. Sour Cream is actively finding work as a DJ in Empire City, and Sadie has found a new musical -- and romantic -- partner in Shep. Her new sound is much more mellow, suggesting Sadie has found a sense of peace with her situation.
LARS OF THE STARS
All of this comes as a shock to Steven, especially coupled with the revelation of Lars' plans. After spending time in space with the Off-Color Gems, Lars returned to Earth in the Season 5 finale of Steven Universe. He eventually opened a bakery and spent time living a normal human life. But with the Off-Color Gems graduating from Little Homeschool, Lars has decided to rejoin them. He's even leaving the bakery to one of his assistants, the gem Blue Lace Agate, so they can return to space together. They even have a new mission: bringing the lessons of Little Homeschool to other Gems around the galaxy.
Steven is particularly shocked by this because he assumed Lars would eventually end up with Sadie. But as the pair sadly reveals to Steven, they followed different paths, and simply didn't connect the way they used to. It's a painful reminder that, while Steven has been occupying himself so heavily with the Gem School, life has moved on around him. It even leads him to lose control of his powers and trap everyone in a bubble during graduation. Although Steven seems to come to terms with everyone leaving to lead their separate lives (yet still connected by friendship), he does at least receive a nice reminder that he can easily teleport to Lars. That teases a future appearance from Lars, back to his old persona as the space hero Lars of the Stars. But things don't get any easier for Steven.
PROBLEMS WITH THE GEMS
Although he's trying to accept the changes his friends have been going through, Steven still has a difficult time watching everything shift around him. That comes to the forefront in "Prickly Pair." Taking a break from Homeschool to try and find his own passions, Steven takes up gardening, and vents his frustration with himself to one of his cacti. But that becomes complicated when his healing/life-creating spit gets onto the cactus. It grants the plant sentience, and evolves it enough that it becomes mobile and transforms into a surprisingly durable monster. But as it attacks the Crystal Gems, it parrots the mean things Steven said about the Gems while he was around the cactus. While the Cactus Steven is eventually convinced to leave peacefully, the episode ends with the Gems seemingly aware of Steven's inner turmoil. However, he only retreats further instead of trying to confront his problems.
Steven has usually been defined by his optimism. Throughout the series, his positive attitude helped to end an intergalactic empire built on destruction. But with his own emotional problems bubbling to the surface, he's lost some of that inherent kindness. He's even bottling up his emotions instead of dealing with them, and failing to live up to the lessons he's taught his enemies over the years.