i watched this too, I can't stand the woman, but didn't really know why.
I don't care one jot that she married a Beatle, yet she's so annoying!
Anyway, after watching the programme, I came to conclusion that she's just not endearing in any way. She appears totally unfeeling and unemotional, and it's that trait that is unlikable.
She talked about being abused, her mother leaving, a very unhappy childhood, and her mother's death - all without a flicker of emotion.
She's like a robot!