I have to admit, I do very much side with Boaz on this one - the first time Cat really stands out from the book is early on, when she tells Jon that it should have been him crippled instead of Bran. You just don't forget that sort of comment easily.
Oh, unquestionably. Many people talk about Ned's death as being the point when they recognised that AGOT was going to be more than your usual fantasy fare, but I trace it to that scene with Jon and Cat. It was a clear signal that we were not going to be given an easy scenario with good Starks and bad Lannisters, where all the good guys like or at least respect each other because they recognise that they're the good guys.
It's clear from that scene that Cat can never forgive Jon merely for existing, and equally clear that she blames him unfairly. She does something unforgivable and wrong. One can point out (as I have) that she was under great stress, that she was equally horrible to Maester Luwin in the next chapter, and that she even seems to have been unfair to Ned, Robb and Rickon in the same period. But none of that takes away from the impact of the scene.
Yet, it's not my first impression of Cat. Cat has, after all, two chapters before that. And in those chapters we see a lot of her good side. She's tolerant and loving and kind. We see that she loves her children, and her husband: that she has made a good, loving marriage out of a political arrangement: that she is perceptive and clever. So, when I saw that scene with Jon, I didn't conclude (as some do) that Cat was a 'bad person'. I just saw that she had a major problem with Jon that could not be resolved, and that she had done something wrong under great pressure. I saw that she was a flawed, human character, something that GRRM specialises in.
Cat, more than any other character IMO, benefits from a reread. When I first read the series, I was inclined to blame her for a lot of things that, on rereading, I reassessed.
She has her faults, foremost among them a lack of humour - but that can be put down to the fact that, of all the characters, she has the least to laugh about. (Her chapters are almost without exception pretty stressful situations.) She can be sharp with others, but at the same time, she sympathises with Brienne when no-one else will: she remembers the name of the woman who used to come begging for shoes at Riverrun: she shows concern for the smallfolk: she even wonders whether Jon's mother worries about him, as she does for her children. She prays for an end to the war, she negotiates passage over the Twins, she comes to trust the instincts of the direwolves (against her initial reaction), and she acts bravely when necessary.
Blind to her shortcomings? I don't think so, really. She acknowledges when she has spoken sharply to others, or said the wrong thing to Robb. She admits when she has made mistakes. Compared to, say, Robert (who was only willing to face up to his shortcomings on his deathbed) she's a freaking saint.