YMMV / Supernatural S 05 E 13 The Song Remains The Same

• Unintentionally Sympathetic: Anna. The last time we saw her, Castiel had sold her out to be taken back to Heaven for the crime of defecting (an act that Castiel himself would do literally by the next episode), where she would be tortured and brainwashed into the fanatical angel she is now. She plans to go back in time to kill the brothers' parents to prevent the Apocalypse from ever occurring, as it was Sam, Dean, and Castiel that had caused it to happen in the first place. Everyone involved ignores that Anna was their ally who was trecherously sold out by Castiel, and instead views her as just another evil being that needs to be destroyed, and not once does anyone even consider trying to help Anna break out of her indoctrination before she is brutally killed by Michael.