I blame her mother and her father but more of her mother. And Joan Fontaine herself has said in many occasions that her mother did not handle the two sisters well and always favored Olivia over her and expecting her to always yield for the benefit of Olivia. And she just spends her life trying to live up to Mother's expectation. Who in this day and age writes the word "mother" with a capital letter "M"? That just says loads, doesn't it?
Joan's behavior is the typical behavior of someone who has serious abandonment issues, growing up feeling never loved, never wanted and never needed by their parents, always feeling ignored and yet spending their whole lives trying to please the people that they feel should love them, first their parents, then their love/life partners, and then their children. And they spend their whole life never feeling secure, having all kinds of anxiety sometimes even to the point of paranoia. Whenever somebody they THINK did not do enough of what they expected, that person is automatically dismissed as "not caring about them", "not loving them", and etc., it might be an innocent gesture or innocent mistake but unless that formerly trusted person spends all the time in the world explaining him/herself to them, that's the feeling that they get: they don't care about them aka they are being abandoned again, not wanted anymore. Like in the book where Olivia forgot to pack her veil when she was helping to pack off her bridal stuff from Joan's hotel room. It might very well be an innocent mistake on Olivia's part but to Joan, I am sure for the rest of her life until the moment she dies, she believed that Olivia did that on purpose out of spite no matter how much Olivia explains to her. Dealing with people with abandonment issues is like walking on thin cracking ice, you never know when and where and/or what you did or did not do and/or whatever you said or did not say are going to set them off because their psyche is just so fragile, thinner than a piece of paper because of the love and recognition that they never received or expected to receive from the ones that they seek love and acknowledgment from. And this is probably why Joan is always coming across as the victim in all situations in the book because that is all she could feel that nobody cares about her.
And not only that, they have non-existent self-esteem let alone self-confidence. They never see themselves as beautiful, or smart or strong. I mean to me, I always thought Joan Fontaine is the prettier and more elegant of the two. Just my personal feeling and I am sure I am not the only one who sees that and yet Joan throughout her entire life, never saw that and constantly thinks she was overshadowed by Olivia. That's very typical of somebody who has abandonment issues. Because they have non-existent self-confidence, they always see themselves as weak and always needing protection because of the lack of acknowledgment that they have received from their trusted ones. To compensate for their fragile and vulnerable self, the people that they seek companionship with are always the strong, confident and protective type, like in the book Katherine Hepburn, Miss Robson, Brian Aherne (in terms of having money and a house at the time of marriage). But they can be fiercely loyal to whoever they feel are the strong and protective type who they think they can trust to protect them and care about them. And life can be great with them until they feel that the companions that they think are strong and are protecting them can't be trusted either and/or don't care about them either then all of the accusations, blame, resentments, bitterness all came pouring out and the relationship whatever that is becomes forever estranged. It is extremely difficult to form any long-lasting, fruitful, close, mature relationship with people with abandonment issues because people with andonement issues live forever in the childhood stage where they are seeking attention from their parents, waiting for that hug that never came... so consequently people around them eventually realize that the best way to deal with them is to keep them at a distance, treat them with politeness and respect but never establish anything substantial or close with them. This is probably why Joan Fontaine has had 4 marriages and all of them ended up with divorces and all of the family relationship with her are all estranged. It is quite sad. When you've ever encountered somebody who has abandonement issues like Joan Fontaine, you actually feel quite bad for them and many times all you want to do is hug them and to take their pain away to make them feel better instead of always living in endless self-loathing, self-pity and paranoia. You always feel that you can; all you have to do is somehow make them see the other side of the story, to see things for what they are then they will come out of their dark view of the world and to make them see everything in the light and themselves for who they are but you can't. You never can because ironically, people with abandonment issues are actually quite strong.
They are always some of the strongest, the most independent and most resilient people that you will ever meet. Because (they feel) there is nobody ever there to support them and help them, they learn from a very early age how to adapt to survive, how to negotiate to get they want whatever they are not getting from their parents or loved ones and most important of all, how to persevere when the going gets tough so as a result, they can be quite stubborn and are dead set in their own view of things and would never change thus unfortunately will never come out their dark shell. But fear not, they do quite well for themselves usually as evidenced by the illustrious, long and successful career that Joan Fontaine had both on-screen and in life. Joan Fontaine was a licensed pilot; it's a rare accomplishment even among women today.
Everything has a way of balancing itself out. Whatever they (think) didn't get from their parents and family, they get it all paid back to them ten even hundred-fold back in their success, wealth and everything. Really happy for Joan for all the successes that she had. She had worked very hard for it and certainly earned it. It's always a great joy to watch her on-screen. I just wished that she could realize that not everybody was as bad as she thought especially the ones close to her and aside from some really callous people that truly failed her, people really cared about her even though they might not have expressed it as well as they should.