(HATED TROPE) Creators trying to make a horrible character sympathetic but they never or barely redeemed themselves
Himiko Toga (MHA): A mentally unstable serial killer with no remorse to her actions whatsoever. Yes, she is a byproduct of abusive parents and her quirks. But that is merely an explanation for her cold blooded actions and not an excuse.
Her so called redemption arcs comes in when Ochako and her had a talk about her past and romance, and resulting in Ochako nearly dying if not for her sacrifice, and that's it. She never once felt any remorse about her mass murder and terrorist actions.
Annie (AoT): Same as above, Annie was a spy alongside multiple people sent to the country the main character was at to infiltrate with rhe ability to turn into a female titan. After she was captured and frozen, with her spy comrads fleeing, she was eventually broken free due to other circumstances in the story. However, in the last few arcs when she was present, she never once showed any guilt remorse or regret for killing hundreds of paradis soldiers. Especially the famous 'yoyo incident' where she was swinging one of the soldiers like a yoyo. She even outright publicly says that she would do it all over again. Her scenes showing her crying were just her crying due to not being able to return home and see father. Unlike reiner, who was deeply in guilt for the killing he done, and even attempted suicide, annie was somehow just forgiven by the main cast and even got into a romantic plot with Armin.