I liked Darnell until the whole Sara thing. He was very creepy around her.
The series with Helen Wood made me so angry.
I thought BB7 was a bad one as well. There used to be a video on YouTube called "Big Brother 7: Mean Girls" where someone had compiled clips of some of the bullying that went on in that series. The housemates' treatment of Shahbaz and Sam was shocking. Grace was vile. Nikki said some awful things too. There were other, more low-key things, like the treatment of Bonnie, which was uncomfortable to watch as well (I remember Lisa singling out Bonnie and Sezer, and saying she didn't like Bonnie because she was quiet. All the other housemates apart from Lea and Glyn, didn't seem consider Bonnie at all). Lea had issues too, she was very paranoid and clingy with Pete and Richard, and would often start crying and having outbursts when the attention wasn't on her.