ANGEL (1999-2004)
For a spinoff of a show that was a TV spinoff to a movie about a high schooler slaying vampires, Angel did pretty well for itself. It lasted five seasons and formally launched the career of David Boreanaz as a vampire working through his human guilt by playing detective to occult problems around Los Angeles. Creator Joss Whedon says though its season 5 cancellation was unexpected — ending with Angel rallying his surviving friends after an already bloody episode — it fits with the show as it demonstrates the good fight is an eternal struggle. So thematically, the cliffhanger works. Emotionally, it sucks.