It's one thing when shows introduce elements of an unlikable character's backstory that make him or her sympathetic. But the way they made Jeb a "sympathetic" character was ridiculous. [spoiler]Oh, so now, all of a sudden, he's a good person, and we're supposed to be sorry for him? And then they tell us that, on top of everything else he did, he killed the series' first heroine, and they still expect us to feel sorry for him? What the heck were the writers thinking? It even continued into Beyond the Shadows, what with Carolyn turning Adam down because she had been truly in love with Jeb? This is writing that belongs on Nickelodeon, not Dark Shadows.
I actually think the way they gave Quentin amnesia was pretty good, especially considering the fact that now, both times we've seen Barnabas drive, he's run over someone!
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And I agree with Taeylor that the Megan and Jeb thing was just pervy and disturbing. But Roger married his grandmother, so stuff like this on DS is hardly uncommon.