One word I never use is boring, I don't believe in boredom. I never complain about them 'bitching' (talking about other HM's) because that's what BB's all about, there'd be no show without it. It's human nature to talk about the others, we thrive on them doing so.
I found Sarah dull, that's why I don't mind that she left. I didn't like that she sat holding court in that little smoking area, with so many housemates running to her for her approval.
The housemates obviously rely on her as the chief cook and bottle washer, but - as a viewer - I found her decidedly uninteresting, much as I liked her in the first week.
ETA: I'd feel the same if she were a bloke