Worst character would have to be Neelix of Troi. They're both pretty hard to stomach. At least Neelix was occasionally pretty funny. Troi was never any good. Even when they had decent stories for her, turning her into a Romulan for example, she was still pretty bad.
And I also preferred Pulaski, simply for the reason that she had spirit. As I've always stated, my problem with the TNG crew were that they had no soul. While she was a bitch more often than not, at least that qualifies as personality. I also consider Diana Muldaur a much better actor than McFadden.
Well apart from the fucked up grooming of Kes,
This really made me LOL.