I watched this over Christmas. I liked the first season a lot but the later ones really drag. The problem is that Catra is by far the most interesting thing about the show, and the first season does a pretty good job of showing that the only thing that actually makes her happy are her relationships (which in the first season is just Adora) but she's incapable of admitting that and has to justify everything in terms of working towards some other goal she pretends to have despite not really caring about the Horde at all. By the end of season 1 she's gone so far as to legit try to kill Adora rather than just switch sides even though she doesn't really care which side she's on. And then she just repeats this cycle over the next few seasons with new characters like Entrapta and Scorpia (and Adora some more), except each time it's harder for her to back down and admit she's been wrong the whole time and so she can justify even bigger demonstrations of how independent she is like opening the portal.
It kind of seems like they're now setting up for her to finally switch sides, but only because it might become clearly in her best interest to oppose the Horde, which is kind of a cop out.
I would suggest that as children, Adora and Catra formed an alliance for survival in the harshness of the Fright Zone, and this turned into a sort of family/relationship bond, but it was so essential for Catra's survival that she suppressed her own wants and desires, always deferring to Adora, for fear that Adora would leave if Catra was ever anything less than perfect for Adora (note that Adora probably never asked for this). Like, Catra apparently had ambitions towards becoming a Force Captain, but Adora openly wanted to become one, so Catra pretended that she
did not want to become one and instead supported Adora's push to become one.
As Catra grew and became powerful enough to take care of herself, she grew tired of suppressing herself, and grew to resent being protected by Adora. This festered into a deep-rooted hatred for Adora.
When Adora went off to find the sword, Catra wanted to come along on a fun adventure (since fun adventure was one of the main positives of their relationship, as far as Catra was concerned), but Adora insisted that Catra should stay behind, to protect Catra, which Catra clearly resented. When the two of them met up again, Catra was having a blast shooting up a town full of innocents (and unlike Adora, Catra knew she was attacking innocents, she just didn't care), and when Adora proposed switching sides, Catra refused, not because she has any sort of loyalty for the Horde (she has no loyalty to any side), but because she refused to accept that Adora had the authority to lead the two of them into changing sides. Catra refused to change sides because
Adora was the one who decided that it was time to change sides. Rather than help Adora, Catra decided that she would rather see Adora fall and be defeated (she was willing to taze Adora and drag her back to Shadow Weaver to be abused).
After Adora and Catra split up, Catra reveled in her newfound freedom to be herself, and reveled in her released hatred of Adora.
With Scorpia, Scorpia is an extremely generous and loyal friend (as a result of those virtues being baked into her by the lies she was told about her family "giving" her land and crystal to Hordak), so she decided to be way too nice to Catra, whom she believed to be entirely innocent in the Adora/Catra breakup. IMO, Scorpia and Catra's friendship was almost entirely one-sided. Scorpia was putting all the work in to be a good friend, while Catra just wanted a loyal/dependable underling. Catra seemed actively annoyed by Scorpia's claims of friendship, because they reminded Catra of her doomed friendship with Adora. Catra doesn't need or want friends anymore.
Entrapta and Catra were also one-sided. Catra never liked Entrapta, she just lied about friendship to win over another valuable underling. And then got annoyed when Entrapta went around Catra and made friends with Hordak (Catra's superior). Entrapta essentially stopped being an underling and jumped ahead of Catra in rank, and Catra did not like that at all. When Catra shipped Entrapta off to Beast Island and threw her under the bus with Hordak, Catra didn't feel anything about that.
It was only after Scorpia finally accepted that Catra was a bad friend and left, that Catra realized that she missed Scorpia, and that she missed the endless amount of work that Scorpia was putting into maintaining their friendship.
