The Worst Thing That Abby Ever Did
Abby did a lot of "questionable" things during her tenure on Knots, but what do you think was the worst thing that she ever did? For me, it was putting the cocaine in Harold's locker.
I get that she was trying to keep Harold away from Olivia. However, by that point, Harold had already proven himself to be not such a "bad" guy. Couldn't she have just let the relationship run its course? She could have put a mark on his record and/or ruined his life, and why? Because he was dating her daughter? For her to screw over her business contacts is one thing. But for her to screw over Harold, just as he was turning his life around, really took it too far.
I'm surprised that Olivia was willing to overlook this and simply use her knowledge to blackmail her mother. If I were in Olivia's situation, I wouldn't let Abby get off that easy. Plus, where the hell did Abby get the cocaine? She claimed that part of her reason for wanting to bring down Manny and his goons was to stop them from getting young people hooked on cocaine, the way Olivia was hooked. And then, immediately after, she went out and supported the cocaine business.
She did a lot of things that were more devastating to the show as a whole, but I think that this was the lowest, most desperate thing she ever did. And it backfired.
(FYI: Abby is my second favorite character on the show. I love every mean-spirited, questionable thing she ever did. I just thought she took it too far here.)